Is this your trade idea or an actual rumor you've heard from some reliable source?
I absolutely hate it if true. Not that Belinelli is worthless to this team -- the added shooting punch would be great. But Marcus' value (IMO) far exceeds Marco's. The loss of Smart's defensive presence and versatility (and play-making capability) at the end of games is hard to replace. Marco is also expiring.
Tyreke, on the other hand, would be good value for Smart -- he can guard multiple positions and can pass the ball in addition to his scoring skill.