one of the reasons it's useful that git-pages is so efficient storage-wise is that i don't actually need to worry about what people are uploading. there are no cases where reasonable-seeming use of the website would generate problematic amounts of resource use, so i don't have to watch over resource use. it's Fine.
someone uploaded two copies of a site containing Every Manpage, which is half a gigabyte (each)? it only costs 36 MB to store it (total). it's Fine.
by designing the whole thing with scale and efficiency in mind, i can be providing a hyperscale-style service without having hyperscale infrastructure, and i think that's a worthy achievement

an amusing outcome of this is that it is almost too efficient. one site i've examined because it showed up at the top of the list of biggest sites. turns out it contained, by accident i assume, an entire copy of ESP-IDF build directory full of object files

git-pages is efficient enough that you don't usually notice these things because something gets slow and you investigate