There are problems with worktree. But yes, I often do use multiple checkout directories. When you do the git clone using the --reference option it gets most of the objects from the referenced directories.

But this still results in slow compile times because the less used release directories get stale, have to be pulled up to date and often mostly rebuilt anyway. If I remember to actually use the second checkout directory, it does save on needing to rebuild the master/feature branches afterward.