having feature/username/id-desc is good though. Because at least you can identify why the branch is there. That they are ephemeral doesn't mean that people actually clean them up...
I understand, but that means you need to review the commits and code changes and do not have the context which could be found either in the issue title, description, etc.
If it has commits I care about, then it stays. If it doesn't, It goes. I'm only deleting on the server afterall, people can just push it back.