[jurgenburgen]

That’s pretty screwed up. So even if I setup e.g. Telegram as an allowed app in my WhatsApp account, I can’t communicate with friends on Telegram because they haven’t (why would they, they don’t even have WhatsApp) configured their WhatsApp to use Telegram?

[IshKebab]

You can communicate with your Telegram friends using WhatsApp. You can't (in practice) communicate with your WhatsApp friends using Telegram.