It's not "critical". If Whatsapp vanished tomorrow it would get replaced by the next one so fast it would make your head spin. Not saying I can guess which one it would be, but one would win and people would carrying on with their lives just fine.
That's not the case with X. Isn't like X (or previously Twitter) ever had the amount of users that WhatsApp have in Brazil.
If I recall, X have 20 million monthly active users, and yet it was the 4 or 5 country where X had most users.
But for Brazil size, this is very ridiculous, WhatsApp have 170 million users in Brazil.
This just shows how Twitter/X is small compared to other networks. It was always a small social network with relevant people.