The manufacturers doubtless know more about their master link (hereafter "quick link") design and its long-term reliability than you or I. If they call their quick link design "single-use", then it probably is - though whether that means "use on one chain only" or literally means "install once, then discard if ever opened" isn't immediately obvious.

The meaning of "reusable" is similarly not immediately obvious; it could mean "can be opened/closed multiple times on the same chain", or "can be used on multiple chains". The former makes more sense, since like chains quick links also wear.

I'd recommend using a quick link that's identified as "reusable", as well as using a new quick link with a new chain. Maintenance might require chain removal, and if you use a reusable link you're covered regardless. They're available for 6/7/8/9/10/11-speed standard chains. (Most if not all 12+ speed, SRAM flat-top, and narrow/wide chain quick links currently seem to be single-use.)

That said, many people seem to get away with re-using "single-use" quick links. Just remember: caveat emptor. You have no one to blame but yourself if you go against manufacturer's recommendations and things go wrong.