At least on my phone, WhatsApp essentially just uses my phone contacts, I wasn't aware that it had any system of contacts of its own. As to storing encrypted da

At least on my phone, WhatsApp essentially just uses my phone contacts, I wasn't aware that it had any system of contacts of its own. As to storing encrypted data on WhatsApp servers, I assume that's an expense that's not needed if they let Google and Apple handle that. It would be nice if there was more flexibility when it comes to choosing where to store data, but I imagine there's not a lot of commercial value in that. The reason why I'm talking about UX and technical limitations at the same time is because they're often linked, and particularly so in this case. The technical limitations of a tool will partially define how that tool can be used, and the desired usage of a tool should often help define the technical functionality of that tool. UX is not simply a layer you can slap on at the end.