I have done remote pair programming many times though and in that case it’s perfectly ok, because you’re communicating with the other person/people and can let each other know if you will break something.
For that use case, I can see this being very useful.
While you could do real-time collaboration on code edits with this tool (and I've done that with some success via pair coding, where you commit them to git after your shared edits are complete), this tool isn't strictly about code. It's about any shared content at all. Think google docs, but for any data, with offline/online sync. The offline/online sync might not be great for simultaneous edits, but in a shared "project" of say, field research data, the combination offline/online sync and soft-realtime shared documents at any hierarchy level layer is a nice "don't need to think about it generally" approach.
I'm not sure which kind of CRDT these are, but since all edits are part of history, as in git, you're not going to lose history if someone DOES inadvertently stomp on someone else's edits.