As a developer consuming their designs on Linux, I care. Most platforms don't check that box.

Most designers use Macs, sure. But just giving a link to product owners, QA, clients, and developers is a whole lot easier than trying to get them to successfully use Zeplin or manually keep track of what static images I've copy/pasted in tickets etc.

Also: I use Mac at work and PC at home. So now you know one designer who uses Figma on PC.

A lot of web developers have been put off Apple due to macOS and Mac hardware issues, and simultaneously attracted to Windows due to WSL. Figma gives them an option to switch.

As a Mac user who has had to Switch my workstation machine to PC for performance anything that reduces my reliance on Apple hardware is a great thing.

I went from a macbook to a surface pro, Sketch was the only thing keeping me on the mac until I switched to Figma. I use it for UI design.

Figma user. As I do real time 3D stuff I constantly switch between Mac and PC.

you're living in a bubble then :) I also was a designer using mac but that was only because the tools forced me to, but in reality I can't afford a proper mac so I now have the option.

About 50% of our local office cares that their tools work on Windows as well.

Figma user myself. Use on Mac at home, on Windows at office. At office Windows machine due to corporate security policies.

Our designer runs Windows. His friends running Windows. I'm convinced. They all use Figma.