It's definitely stable enough for doing "real work" on, though the lack of GPU accelerated timeline playback can make some more complex projects a little difficult. I've used it for proper work plenty of times over the years (I survived the Covid lockdowns entirely with paid video editing from home, on Kdenlive, as my normal work was unavailable).

I still frequently save manually with a new filename, due to old version paranoia, but if I'm honest, it's own "it saves every click in an ongoing temp file" sort of thing works great. You lose 2 seconds of work, then restart and restore.

Basic edits are likely to have no crashes at all, wheras ones where you, for example, pan and zoom with keyframes, then speed up, then reverse the footage, then try to re-edit the pan and zoom, might get its keyframes in a twist and crash frequently.

I've heard the Windows version is less stable.