The CFC commentariat often weighs in that perhaps Tottenham takes the Europa League a bit too seriously, but it's worth noting that success -- both in the competition overall and in individual games -- could be vital if Tottenham wants to compete in the Champions League in the coming years. The reason for this has to do with the somewhat strange way that the Champions League is seeded.
Each year, when the competition is down to its 32 group-stage clubs, they are seeded 1-32 based on the "Club Coefficient", which is meant to reflect the strength of the individual club. The clubs are then split into 8-team pots: Teams 1-8 in Pot 1, 9-16 in Pot 2, etc. There's no difference for seeding purposes between being the best team in the competition and the 8th best, but there are huge differences between eight and nine, or 16 and 17. How big? Well, pot seeding is a fairly good indication of whether or not a team will advance. Below is how teams from each pot have done in the last five years, in the format of "Pot: % advancing to knockout, % dropping to Europa League, % out of competition":
Pot 1: 90%-10%-0%
Pot 2: 60%-18%-23%
Pot 3: 35%-38%-28%
Pot 4: 15%-35%-50%
(Note that last year was a strange year, as 3 teams from each of the last three pots advanced. For the previous four years, the knockout distribution had been 91%-66%-34%-9%)
So we want to be in one of the top 2 pots -- how do we get there? The Club Coefficient is calculated based on the sum of a club's performances in Europe over the previous five years, plus a small bonus based on what league the club competes in. Tottenham's current coefficient ranks it 21st in Europe, though that number is still being dragged down due to the club's lack of European competition in 2009-2010 (the last four seasons' totals -- which, along with this year's, will be used for next year if needed, are: 4, 25, 10, and 19, respectively). The difference between the current #16 club and Spurs is ~10 points, while there are 15 teams that trail Spurs by 10 points or less. Note that Spurs don't necessarily have to be team #16 to be in the second pot -- it all depends on who makes the group stages. This year Inter was not in Europe at all, while Lyon didn't make the group stages, so two teams outside the top 16 made pot #2. Next year, if Spurs qualify for Champions league, there's a good chance that one of Arsenal, Chelsea, or Manchester United (all with high coefficients) would not make it.
Okay, so 10 points up or down can be the difference between definitely pot #2 and definitely pot #3. How do we score points? I'll warn you, it's a bit strange, but it benefits us:
Teams in the Champions league get 4 points for making the group stage, vs 2 points for making Europa league group stage, and an additional 5 points for making the knockout stages (vs. zero additional for Europa). Beyond those 7 possible points, points are earned identically in each competition: 2 points for a group stage win, 1 point for a group stage draw, and 1 point each for competing in QF's, SF's, and Finals.
You might be taken aback by that, but winning on a Thursday night in Moldova on day 5 of this year's group stages, with advancement already locked up, will give Spurs 2 precious club coefficient points -- twice as many as Dortmund got for knocking out Real Madrid over two legs last year. The takeaway here is that points are much easier to come by in the Europa League than in the Champions League (though those bonus points are nice) -- and it makes a non-negligible difference whether you win your Europa League group with 18 points, or sneak by with 8 points: It could be the difference between pot 2 and pot 3. And not just for the following year, remember, but for the next five years.
Look at two teams: Atletico Madrid have the 11th highest club coefficient in the Europe right now, thanks overwhelmingly to its two Europa League runs in 2010 and 2012. They were less than 3 points away from being seeded in Pot 1 for this year's group stage, and were actually unfortunate to be drawn against Zenit, the 'best' team in Pot 3. Man City, meanwhile, on the back of its missing Europe in the 'out' years (Pre-money), and its poor performances in recent years, found itself in the third pot. They were fortunate to be drawn against one of the lowest teams Pot 2 (CSKA Moscow, above only PSG and Juventus in Pot 2, each of whom are better than their coefficients suggest due to low scores in the coefficient 'out' years, due to lack of funds and corruption, respectively). How much better would City have needed to do in any one of the previous five years to have ended up in Pot 2? Less than a point. If only that loss at Lech Poznan in the 2010-2011 Europa group stages had been a draw...
So, the point is this: The Europa League is a great opportunity for Spurs to pad their club coefficient for the next five years, which will allow them easier games in the group stages of the Champions League (or Europa League, again). Whether or not you think "winning the Europa League" matters, it's clear that, if you want to be a successful team in the Champions League, it's important to win in the Europa League. If you think to yourself, "Why are we playing such a strong team against the Moldovans when we already have our group wrapped up?" remember that it's worth two potentially vital points.
Thanks for listening, sorry it was so long, let me know in comments if any questions about sources etc. (Wikipedia has entries for the group stage of each competition, for each year, which show the teams' coefficients and the pots)
1) Full coefficients are here -- these are the years that will be used for next year's draw (i.e., one of the years used for this year's draw has already been lopped off the front end)
2) You'll notice from the rankings formula that leagues with parity are sort of punished -- Germany has had a fair amount of rotation in the last few years, so has teams that are new to Europe, despite being really quality. England, however, have consistently fielded the same three teams in Champions League, so all three were in the first pot this year.
3) Man City beat Lech Poznan 3-1 at home, and lost 3-1 on the road. The same player scored all four goals for City. Take a bow, Mr. Adebayor.