Somehow sad, but on the other side - email is a privacy nightmare. Even worse than WhatsApp I guess.
Discussion
WhatsApp is directly linked to your registered telephone number. Hard to be much worse.
And email can be encrypted. Comes standard with Exchange and you can select it is OWA.
Also note: their second option was just using Discord.
WhatsApp is registered to "a" phone number. Can be any.
Email can be encrypted but it's hard, depends on the provider or software that you use and the problem is key exchange.
I don't like either option, let alone Discord or FSM forbid - Telegram.
But that is a good demonstration of the problem - it's about network effects.
isnt gmail and most email providers accounts linked to a registered phone number too?
if whatsapp commited to what they say about end to end encryption i think its ok, most people dont know how to use/install email encryption like PGP or S/MIME
Encryption is standard in many email clients and servers, now.