Earlier quoted context omitted.
Do you feel like WhatsApp is not polished?
If polish is broadly defined as "something that was hitherto still missing in (claimed-to-be) end to end encrypted chat applications", then open source and a decent profit model are definitely features lacking from WhatsApp. Telegram is open source, but one has to consciously turn on encryption and it doesn't work on the web or desktop clients (and the profit model is non-existent). Signal doesn't work without Google…
You can even send E2E-encrypted messages/files to people who haven't even joined yet!