In terms of who needs binary blob diffs, yes, its an overkill. In terms of having easy to set sync method anywhere it works beautifully. Pass has integrated git commands so pass git <command> does everything that git does. Commits are automatic with every change so all I need to do is "pass git push" on one machine and "pass git pull" on another to keep everything in sync.
I haven't used `pass` yet so I haven't tested this. But I would expect them to make git threat hashed passwords as binary. That would make git more like a file system with history, which is just what you want for a password store anyway.
Assuming you're randomly generating passwords, the diffs basically amount to storing all prior passwords; fine, but git seems overkill for that?