Might be different in other countries, but in Germany its only used by them.

In what country do you live? I live in Germany and not even iPhone users use iMessage.

Germany uses Whatsapp and Signal. Whatsapp for the older generation, Signal for the younger ones. But almost everyone has both. Telegram is a niche messenger for conspiracy theorists and alt-righters, because it’s russian and those people love Russia.

Maybe for 2FA. But for messaging with friends and colleagues? Everyone uses Signal, Whatsapp or telegram.

I have the P8 pro with 4G. And I barely drop below 40 % during the day. And that with plenty of screen on time.

To be fair, the secondary sensors are not the same, only the main sensor.