Spurs probably envisioned themselves making a bit more of a profit on Fryers when they signed him away from Manchester United/Standard Liege, but they've still managed to make a profit. The now 21-year-old was controversially signed for a very low fee from Standard as a way to circumvent a tribunal process.
Fryers was probably never going to break into the Tottenham Hotspur first team, but he'll provide some decent depth for Crystal Palace. They don't have a big squad, so it'll help that he can play both central defense and left back. Their central defenders are a bit better than their fullbacks, though, so he'll probably play a bit more on the left.
All in all, this is good for everyone. Spurs get some money for a player that was never going to play for them, Palace get a cheap depth player with potential to become a starter and Zeki goes somewhere where he gets to play. Win-win-win.