I'd just like to add my vote up for these types of masking features. Yes, there's almost always a workaround for things and I do love the rulers, stencils and selection options we currently have access too. However, having these types of masks would greatly reduce workflow tasks, by eliminating the needs to hide/show the stencils repeatedly or having to keep separate layers for the sole purpose of having to reselect an area. I'm happy to hear that it's been put on the consideration list.
Nothing is easy to the unwilling.