Why the Hawks do it? They don't want to pay Dejounte's extension and trading Capela clears the way for Okongwu. They also consolidate some of their talent, which I feel they've been needing to do for a while, and get a higher ceiling player than what they are sending out.

Why the Clips do it? They've been trying the PG and Kawhi pairing for a while without success. This trade gives them better center depth and a strong point guard, something they've been lacking.