Looking up his stats, he shot 48.8% from inside the arc in college. In the NBA so far up through age 22, he's shooting 42.0% from inside the arc. Is 48.8% inside the arc good in college? I don't really know what a baseline for "good" or "great" is tbh for college guards.
Thought I'd look into this by finding out what the 2pt% is for guards/wings who are top 6 picks (or projected such) over the past few years. Before I look up the %'s, I'll note that the best comparison players for Smart in this list I think would be Jaylen Brown, Kris Dunn, Oladipo, DAngelo Russell, and maybe Josh Jackson.
Fultz - 50.2%
Ball - 73.2%
Josh Jackson - 54.9%
Fox - 52.0%
Tatum - 50.4%
Ingram - 46.4%
Jaylen Brown - 48.2%
Dunn - 47.6%
Hield - 50.8%
DAngelo Russell - 47.9%
Smart - 48.8%
Oladipo - 58.5%
I guess compared to other top 6 guard/wing draft picks over the past couple seasons, he was never really "great" at finishing inside the arc. He was probably good compared to the rest of college basketball players (anybody have a baseline comparison figure for that?), but I don't think this finish inside the arc was something that really separated him from others in college. If anything, he's clustered around the kinds of guys in this list that you tend to classify in the inefficient bunch.
EDIT - slowly going back further into 2013... Dion Waiters (51.3%), Beal (54.1%), Lilliard (49.7%). A lot of the over the past few years that are really known for their outside shooting rather than their inside finishing still are either better than or not much worse than Smart.