When I'm hunting a mistake (even/especially my own) finding the commit that introduced the bad line via blame and then looking at that specific diff is extremely handy. Also being able to bounce back and forth between the first broken one and the one before running tests while I work out exactly what I messed up and how.

I wouldn't say I put the effort in to get to 100% clean but something like 95% clean makes future me significantly less enraged at past me's mistakes.