Sell me on him.
Strengths?
There are similarities to Kuz in that he looks like an SF but has length like a PF. I'm not sure what got him in the dog house this season, but he always seemed like a high IQ player with enough of a jumper to force his man to stick to him and he wasn't one to force much of anything either. If you replaced Ndour with Casspi, it'd give us a skilled back-up PF for the times when we can't get away with the double Center stuff. The more Kuz emerges the less we need to bother at all, but in terms of improving depth, Casspi would just improve Hornacek's rotation options on an expiring contract.
Basically, adding Casspi would make Ndour expendable so that we could make room for Chasson Randle. But regardless, I don't think we have the pieces to get him or at least the guys who could be dealt for a Casspi aren't the ones I'd want to move.