If I had to be perfectly honest, I agree with Nerf and see Smart becoming a really, really good player.
I do not know if he will become an all-star let alone a HoF like DJ.
But I've been impressed in two ways by him:
i/ everyone was talking about his D before he arrived to the C's, but it's even better than that.
Did you watch him play against Harden? Did you see how he got this last minute charge from Harden? Did you see tonight against Miami the block, then the last minute steal? These are not the kind of things that you will get you in an all star game, but they might turn defeats into wins. And with his hustle he leads the team by example.
ii/The kid is improving. He came to the C's with the reputation of being a bad 3p shooter (29% at college). This season he shoots 37%. 37! It's not about the % per se, it's about his ability to recognize his own weaknesses and improve.
So, yes, I agree the hype surrounding him is excessive, fans are always and everywhere like this. But this kid has promise.