I have tried Mint, and there was a update mechanism - it was either Ubuntu's do-release-upgrade or something on top of that, I honestly can't remember. But the system didn't look like a normal installation after it, that's for sure. Fonts were a bit weird, some settings were migrated and some weren't, it didn't feel right.
I haven't used mint in ages (I used LMDE for a long time though, exactly because it was rolling release), but back in the day at least, the official upgrade procedure was basically "just reinstall lol", maybe it changed now