Another point besides the tooling: Lots of companies are hiring and holding a11y engineers in high regard, if one needs to learn these anyway why not put this new skill to use and make the world a bit better for people with disabilities?

I know that a11y is a requirement is lots of places, e.g. education -- you cannot sell a software with UI to a school if its not accessible. These companies are constantly on a lookout for people who know a11y tools well, and are often in a dire need for people who use these first hand.