I'm not sure MCW isn't a better fit. Since he plays a different position he should be evaluated differently. With this trade on the table we had two options:
Keep Snell and run a 2nd group with either Canaan/Grant/Dinwiddie at backup PG, then running McDermott/Snell at the wing, and probably Niko/Felicio in the post.
MCW runs point, Mcdermott can be paired with Valentine or Zipser or another PG, then Niko/Felicio.
I like 2 because it improves defense in the 2nd group and gives us as close as a true point guard as you can get for a bench group, and also allows guys like Zipser and Valentine to develop and contribute, and really doesn't give up much shooting, either.
Snell has always seemed to have good shooting ability but was only 32% from 3 last year, and is under 40% fg shooter in his career. So it's not like we are giving up a young Klay Thompson. He's just not a plus scorer in any way. Valentine and Zipser could both easily replace 35% from 3 and should be over 40% fg shooters, and we probably don't lose much wing defense with them either (but we do gain defense at the PG spot.)
I get that Snell seems to stretch the floor, but execution matters. And this isn't in any way aimed at you personally because even I have made the "fit" argument. But I hear it a little too much on this sub and in the mediea. It's just more complicated than "MCW can't shoot."