Wild to think that these have been a thing since at least the '90s. And fonts keep getting so much more complex, so there's basically always a reason to use one, if you use different fonts for your daily work for example.

Even so, desktop font management tools seem like they've always been these third-party tools; you don't have closer integration in the desktop space of memory-saving features even close to what browser devs work on. Like more clearly managing browser tab (font) resources dynamically when not in use / not likely to be used anytime soon.