Pero plays solid team defense and extremely good post defense. He draws tons of fouls, sets hard, timely screens, boxes out, draws out the opposing teams big mean to the three point line, packs the paint on defense, etc... He might not get a lot of blocks, but he sure diverts a lot of shots.
The reason he doesn't get a lot of blocks is because he doesn't take risks around the rim. If you watch him, he exclusively goes straight up with his hands straight up when he's defending in the post unless he intends to foul. This makes opposing players furious because they don't catch Pero on gambling hand-slap fouls while theyre in the act and dont get calls for hard contact because they run into Pero as opposed to the other way around..
He generally does a great job of disrupting and frustrating opposing bigs.
He's also shot pretty well in the past 3 games against top flight competition. He is 4/6 from 3 and 8/13 FG over the last 3 games.
I think Pero drew 3 fouls in a row in the 4th quarter when the Mavs were making a huge run, severely disrupting their rhythm and allowing us to stay in the game.
Unless you think Budenholzer is an idiot, then you have to imagine he has a reason for making Pero our primary backup big man. Or, you could think that you have a better eye for evaluating talent than our coach who has managed to make this one of the most impressive seasons the Hawks have ever played.