If you can please explain a bit better how exactly are you using mobile phone wallets as ''nodes'' and emails, because this sounds to me like a privacy nightmare.
You say there is no central authority but most email providers are centralized and they track and read your emails like gmail for example that most people are using nowadays.
Sorry but I see a lot of holes in your theoretical medium post.
You are right, most email service providers are centralized nevertheless you can find good independent email service provider as well. Usually they are not free.
But you misunderstood the concept of email and mobile as a server. The basic idea is:
You need a way to find out by others and finding others by you. In our classic internet you have a domain name which is totally centralized. Using email is a decentralized solution. You can create and change your email address million times with no cost. Of course email service providers usually do KYC, but it has less effect on Sabu protocol since all communications between mobiles are PGP-encrypted. As we all knew protecting privacy has different levels and if you want more privacy, just use privacy-care email providers. It is your choice, meanwhile there are some improvement proposal which I prefer to talk about it later.
For now we found a network of mobile wallets which are working purely peer-to-peer. Each mobile has a list of its friends and communicate with them(send and receive Bitcoin) and do not need any central server.