so it's a NIP-78 version of the settings app, here's the choice of a service for this purpose, why do you need trust?
Hum.. it has nothing to do with NIP-78 because it is not client-based. Its more like relay lists: you just select a few for the app to use. Trust is needed because they are doing the calculation for you and there is no way to check if the calculation was done correctly.
I don't understand how it's different, choose a host image service, Proxy user media, cache, and this would be a service to calculate your followers, zap and WoT.
That's correct. But none of those settings are saved on NIP-78. They have been generalized to be used by any client.