There’s not really an answer to this question. The Apps feature was nothing more than an experiment right back at the beginning of Ghost’s life - same for filters. The only thing I know for certain is that concept will change a lot and the naming will change completely before any of it becomes official. We aren’t actively working on it either although there are plans to revisit some pieces later this year.
I think you’re a little ahead of your time here. I’m going to write something a little more comprehensive on your other topic…