My co-founder is also a long-term Objective-C developer and we have different "styles" of programming. When I write code I care about style but only to a certain extend. When I edit my co-founder's source code I simply adopt to his style and that's it. No need to "formalize" anything as long as no really dumb code formatting rule is used that has real technical drawbacks like:
if(expr)
doThisOneLinerWithoutCurlyBraces();
A tool like this certainly has its benefits though. Depending on how experienced your team is you want to give junior developers automated guidance.
What would be really cool though is if the formatting rules were applied by Xcode itself. Then each team member could have individual coding style settings. Before pushing to git a "company wide" rule would be applied. This has drawbacks as well: gif giff becomes less useful for sharing between co workers, debugging information is out of sync...