I think Smart got lulled into shooting form complacency over the summer, when he should have had a top shooting coach rebuilding/fixing it with him, after putting up a surprisingly average average on 3's in his rookie year.
If he can't shoot them above the "Mendoza line" with the defense giving it to him, he shouldn't be shooting them at all. And if the defense is actually guarding him, he should use his vaunted PG skills to find an open teammate instead.