The biggest problem I ran into without a code formatter is that team wasted a LOT of time arguing about style. Every single MR would have nitpicking about how many spaces to indent here and there, where to put the braces, etc. etc. ad nauseam. I don't particularly like the style we are enforcing but I love how much more efficient our review process is.
Personally I think a lot of programmers care way too much about consistency. It just doesn't matter that much if two files use indentation / braces slightly differently. In many cases, it just doesn't matter that much.
Also your eyes are good at seeing patterns. If the formatting is all consistent the patterns they see will be higher level, long functions unintuitive names, missing check for return success; make bad good look bad is the idea. Carefully reading every line is good but getting hints of things to check more deeply because it looks wrong to the eyes is extremely useful.