From a personal standpoint:
He sucks (or at least allegedly) as a person.
That said, if I'm not missing something, this stems from an issue back in 2016, the domestic charges were dropped, and nothing has come about since. Someone feel free to correct me if I'm wrong and there is something else. (I advocated for his signing earlier in the off-season, someone, I think
@chawson pointed out the allegations from 2016 which I admittedly had no recollection of).
From a baseball standpoint:
Since that time Theo traded for him once and he was a huge part to the Cubs winning the WS. I can see this as a low cost move that helps the 'pen, gives them someone to close and someone that can be used in a set up role if they are able to land someone else. If you're not going to trade Duran for pennies on the dollar for being an a$$hat and showing no contrition, then I get singing Champan as something that tracks.
People always want to be the Braves, and they have players like this (Marcell Ozuna), same with the Dodgers (Urias, the first time back in 2019) or even just the 2003-2019 Red Sox and it's not like the presence of Steven Wright makes me think any less of the 2018 team.
In summation - he's (allegedly) a horrible person, but from a baseball standpoint he's a good fit as a proven closer that can also pitch different innings and for better or worse hasn't exactly sunk clubhouses.