Code style is one thing - formatting that is - but there's others like how features are implemented tend to change over time and with different developers as well, which is difficult to automatically test and hard to keep in line except with good code reviews, but for that to work you already need to install a culture of consistency, which also means that innovation may be stifled and developers demotivated (e.g. because the better solution requires the 100 existing solutions to be rewritten, which is too expensive or requires a whole team to be blocked until it's done).

Consistency trumps a lot of things IMO, but not everyone is on board with that... myself included, I'm guilty of breaking with my own consistency all the time.