[alerighi]

Well this is also a problem. As it's said in the article, you risk getting charged for an SMS, that in some countries are expensive, most mobile plan in my country have 30+Gb for 7 euros at month, but SMS are 20 cent *EACH*. Practically in my country nobody uses SMS, and SMS are used only to receive 2 factor authentication codes (and spam).

Anyway a normal person already uses multiple messaging applications: WhatsApp, Telegram, Facebook Messanger, Instagram direct messages, the good old email, SMS (I guess somebody they are still used reading the comments), adding Signal it's not that big deal.