Do you have questions for the community team? Ask them here!
Currently the server side of snaps are closed source and impossible to self host. Even if you setup your own store the snap binary has the store hardcoded in meaning you have to recompile it with your store.
Having the ability to set custom stores or host your own server helps reduce issues like network latency. Why are snaps essentially vendor locked? Flatpaks allow you to set custom servers which allowed people to make mirrors closer to certain regions fixing issues such as low network speed or high latency.
One assumes that you have already read https://merlijn.sebrechts.be/blog/2020-08-02-why-one-snap-store/ , by @merlijn-sebrechts, which covers precisely this question in great detail.