It’s unstable in the sense that it doesn’t stay the same for a long time. Stable is the release that will essentially stay the same until you install a different release.
Sid is the kid next door (Iirc) from Toy Story who would melt and mutilate toys for fun. He may have been a different kind of unstable.
Neither is unstable like an old windows pc.
It was not a good tool even for that. On many windows versions, you’d actually get malware just starting it up to a vendor page with ads before you made it to a Netscape/Mozilla/fire* page.