Because it's slow and difficult to use compared to sketch. Plus I need my files on my drive 100% of the time and routinely work without reliable network access.

I get kind of why Figma is popular, it solves issues with sharing and collaboration. But the day to day usage is crippled by the fact it's in a browser and not a standalone app where I need it to have total control over keybindings and shortcuts for my workflow. Meanwhile in the browser, hijacking that behavior is a UX antipattern.

Sketch is just so much less cumbersome than Figma it's not even funny. It's easier to use than illustrator and Xd too.