It will be a hard sell for me to switch, that's for sure. I am already using Whatsapp for Western contacts, Kakaotalk for Korean contacts, and WeChat for China contacts. I don't have any Japan contacts currently, or else I'm sure I will have to install Line. I installed Signal on my laptop for one heavy-privacy-proponent friend, and had Telegram for a while for another friend's group business chat, but I never really used either.