This is one of two reasons for trading for him. He leads the league in innings pitched, and this is a staff that desperately needs innings covered just to get them to the playoffs.
Second, he's been very good against LHH (.685 OPS-A this season). If they are going to get past the Phillies/Dodgers, they will need pitchers who are effective against LHH.
Like I said in the initial post, I'm assuming Skubal doesn't happen. I'd love it if it did, but I don't see the Brewers giving up the prospect haul for an impending FA, and someone is going to overpay based on his start yesterday. But Wacha has been more effective against LHH this season than Skubal (.758 OPS-A vs LHH, .577 OPS-A vs RHH).
Casey Mize has been even more effective against LHH this season (.488 OPS-A), and would cost less than Skubal. But he's never thrown more than 155 innings in a season. Will he run out of gas in October?
If you don't like it, then suggest someone better. And be specific about who and not cop out and say, "think better".