Nothing can get a team of engineers bikeshedding like discussing coding style.

Tabs or spaces? What should multi-line conditionals look like? What kind of quotes should we use and under what circumstances?

It might seem trivial, but there are some good reasons to choose a style guide (or create one as a team) and stick with it:

All code feels like your own

When I roll into code that is a mess formatting-wise (a fairly subjective measure!) I tend to judge it negatively, and when hunting for bugs I fixate on it.

After all, if the person who wrote it wasn't careful about formatting what else were they sloppy about?

Of course there's no law that says that poorly formatted code is any worse than other code. A strong style guide removes this issue completely, and keeps you from pre-judging code written by others.

Reduces cognitive overhead

Style is subjective, but long term, code is written to be read.

There are many valid styles, but sometimes hopping between files that are formatted differently can feel like reading a book where the format changes for each paragraph. Sure, you can read the book - but it is distracting.

Ideally the only thing you're thinking about when you're reading code is what it does.

Tidiness makes you feel good

For me, aesthetically pleasing code makes me feel happy. I bet that is the case for a lot of coders who take their craft seriously.

Would you prefer to work in a clean room or a cluttered one? A codebase is like a shared living space - everyone has to pitch in to keep things neat.

Ultimately I doubt that the style guide you choose matters very much, but there are compelling reasons for choosing one, and sticking with it!