I don’t think this is a great solution for, broadly, consumer sites and apps.

In a lot of cases, branding matters, and having consistent cross-platform rendering matters.

However, I’ve had good experiences using system-ui with in-house dashboard-y apps. I’m the principle UI designer at my startup, and I recommend this font stack for anyone coding up internal-use-only observability tooling and monitoring stuff. We’re all on Chrome, we’re all on Macs, and getting SF Pro on the page without having to call a CDN or manage font assets is a win.