[munificent]

Two things:

* It can give you an understanding of how your own brain works, so you can better tailor your life to your strengths and weaknesses. Obviously, any amount of self-reflection will help with this, but an actual autism spectrum diagnosis will give you some insight into which aspects are actually biological and very hard to change versus potentially more mutable.

* It will help the people around you better understand you and which parts of your behavior are your "fault" and which are because of your brain. Many of the classic ways that autism presents itself would be hurtful to other people if done by a neuro-typical person: talking over someone, shutting down when stressed, avoiding social interaction, not picking up on signal, etc. All of these come across as selfish or uncaring if you don't know that that's how the person's brain works.

In practice, I think the latter is more useful than the former.