I guess that goes along with the “hard to learn/use” for package creators. I have come across a couple packages that seem to do the packaging wrong, like Delta Chat recently updated to the tune of 500 megabytes, and I already had it installed! Most apps when they get updated download a few kilos here, a few megs there, but when I complained about it to the devs their response (on more than one occasion) was something like, “Well that’s just how Flatpak works.” I suspect though they’re doing something wrong and their packaging process could somehow be improved.