Out of curiosity I checked Dropbox:
https://www.dropbox.com/plans/storage
9 USD per month gives you 2TB storage (vs. 500GB here)
I don't really get what justifies the 4x price (some of the features look like what you can get from a Gallery app like Aves) So it's looking kinda DOA to me.
The intersection of people that care about open source and people that want to backup their photos also seems really minuscule. If Dropbox goes rogue and you need to switch providers.. that doesn't seem like a big deal? It's nice here that you can in theory selfhost and keep using it.. but that doesn't seem like "a big win" either. Most people that back up their pics in ~the cloud~ won't have the technical skills to do self-host
EDIT: There is a comparison: https://ente.io/compare/ente-vs-dropbox/
It seems like the added feature boils down to automatically encrypting files. With Dropbox I guess you could accomplish the same, but you'd need to encrypt manually. Maybe for people with a lot of dick pics or illegal material this product is worth the 4x price