Haha true, and I'd definitely agree that Chromium's borders are one of the least important parts of the software.
However, just because something is less important than something else doesn't mean it's not worth changing.
I doubt most businesses would leave lots of ugly graffiti on the side of their bike shed, even though actual business operations were much more important.
Bike shedding refers to being so distracted by unimportant details that important business isn't taken care of. It's possible to give the shed a good coat of paint once in a while while still taking care of more important matters.