Burks and DeRozan would be redundant.
I agree with this. I don't know why Toronto would want Burks when they have Derozan.
#1 Derozan can't shoot threes, Burks can. Burks is a potential 40+% 3 point shooter, especially on a team that runs a proper offense.
#2 Bench depth. Toronto needs it, and they need to rest players like the other top teams are.
#3 Injury protection. Redundant on a team making a push is a good thing.