The GUI is not as important as another modifier in .stignore :)! But it would be good for mainstream adoption, true.
Unfortunately this workaround is everything else than elegant. I came with help already to this workaround for the moment, but I really do hope that it will be implemented. Why? It’s one of the first features a user is looking for when he has lots of folders and data… Being not able to offer it, can be a killer argument.