I think the idea is perfectly fine and if you want to learn more about these apps and about designing decentralized architecture then you should try it out!
I'm personally a fan of the "dumb pipe smart endpoint" microservice style of approach.
It does have client/server separation but allows all processing, authentication, etc to be done on the users device with servers basically acting as relays for routing that cant access any actual information and Id love to see it used more but for a variety of non-technical reasons, I doubt it
If your interested I'd love to chat more about either of these concepts :v
Ive been a similar idle thought for awhile, abusing file attachments on popular sites to waste bandwidth and storage