This is kind of unfortunate in this case as it breaks some tooling since the extra trees are not collocated with git, like editor inline history/blame or agents that know to look in git history to fix their mistakes
I think the biggest benefits of colocation are, in rough approximation of the order I encounter them:
1) Various read-only editor features, like diff gutters, work as they usually do. Our editor support still just isn't there yet, I'm afraid.
2) Various automation that tends to rely on things like running `git` -- again, often read-only -- still work. That means you don't have to go and do a bunch of bullshit or write a patch your coworker has to review in order to make your ./run-all-tests.sh scripts work locally, or whatever.
3) Sometimes you can do some kind of nice things like run `git fetch $SOME_URL` and then `git checkout FETCH_HEAD` and it works and jj handles it fine. But I find this rare; I sometimes use this to checkout GitHub PRs locally though. This could be replaced 99% for me by having a `jj github` command or something.
The last one is very marginal, admittedly. Claude I haven't had a problem with; it tends to use jj quite easily with a little instruction.
