I don't recall seeing White play. It is a lot to give up. The Celtics must feel he is going to be a valuable long term piece at a reasonable cost. I don't know if he is more PG or Combo Guard though. For what they gave up, it would seem they view him as a starter, maybe replacing Smart.
Smart is so versatile, he can be useful coming off the bench I guess. If they are planning to trade Smart, I hope they get back a good PF:
White
Brown
Tatum
Good PF for Smart
RWilliams
We have 3 open roster spots and multiple TPE to round out the bench. As it stands, assuming Smart continues to start (and why not, that line up has been great), we have Schroder, White, GWill, Freedom, Pritchard, Nesmith, Fernando for the bench, not great, not horrible.