Well, you have to fill in how the downloading and the uploading is implemented, but the orchestration of when the steps save→download→merge→upload should be done, that's pretty useful IMHO.

Yeah... locking the file on the remote would be the absolute minimum for an actual sync tool.

Hmm, I guess, you could upload a lock-file, then download the database + re-upload with changes, then delete the lock file.

I mean, I do get why they didn't implement it (yet), as it adds quite a bit of complexity and it's just not relevant for personal use.
Hell, at $DAYJOB, we used to have a KeePass database on a share for the entire team, where everyone would just hit save whenever, and I'm not aware of there ever being a problem with conflicting edits, because you just don't add/modify passwords that often.