Eric Maynor has not been what the Wizards expected him to be as the back up point guard. His passing style might work better in Cleveland than in Washington where a shot creator point guard might work better.
In Cleveland, they really need a small forward if they want to make the playoffs. Trevor Ariza can play the type of defense that Mike Brown wants from that position and help stretch the floor for Kyrie Irving.
The Cavs appear to be having buyer's remorse on both Jarrett Jack and Anthony Bennett. Both players are on 4 year deals and the Cleveland may be better off cutting their losses now similar to how the Kings traded Thomas Robinson last year.
Both Ariza and Singleton are on one year deals so this move could help the Cavs make the playoffs this year while giving them more cap space to make a move in the offseason (LeBron anyone?). For the Wizards, they could get a player in Jarrett Jack capable of creating his own shot off the bench while buying low on an undersized power forward in Anthony Bennett.
The ESPN trade machine says Cleveland wins this trade, but I think it could help out both teams.