It's a way to stand out in a field crowded with junior and mid tier developers. Show up and talk a big game, and certain other people will listen and assume you're an amazing asset. Not required and perhaps jaded, but it also helps if you have even a tiny semblance of an influencer lifestyle or a type of WeWorkian God complex.

I had a guy tell me once that "if you're not making at least $250k a year, then you failed as a developer". That was his honest life and career advice. It's depressing.