Same here. As outlined below, we tried to use bookmarks for feature branches a few times and it either doesn't work or we can't figure it out. We used permanent branches for feature branches for a while, but too many of those (even closed) would slow down the repository eventually.
Our coping strategy is MQ. It's not the same, but solves the problem pretty well IMO. MQ patches can be sent around and backed up, so not being able to push them to the server is not such a big issue. Takes a little upfront investment to figure out how they work though, Mozilla has a pretty good guide [1].
From what I've seen, bookmarks are not "branches" in any sense, really just pointers to commits.
I've tried several times to use bookmarks for feature branches (read: branches developed in parallel to each other and the default branch). I thought I just can't figure it out, but it really seems impossible at this point.