Progressive enhancement is a real thing and as the browsers start to implement native support for the rest of Web Cryptography API the situation will only improve. We have to start somewhere.
We get compared to other messaging services quite a bit, the big difference is that real-time messaging will not be our only service.
We are already working on other services that will cover the most common needs of developing apps (data store, cdn). The new Identity service combined with real-time messaging and our upcoming services will allow developers to very quickly develop really powerful applications. I don't think that is something businesses exclusively in the real-time messaging space (like firebase) are working towards.