Imo the main thing my education provided was that it forced me to learn the "boring" stuff that I might not have bothered to learn otherwise - especially not if I was focused on learning practical skills to land a job. Things like approximation algorithms, Haskell, all sorts of math, etcetc. Things that I will likely never use directly, but that inform my decisions just by being aware of it.

It also helps a bit with imposter syndrome to have that piece of paper, at least for me.

Neither of these are what I would call strictly necessary, though, for sure.