every single Brazilian bank for instance

Brazil is screwed anyway from what I heard about WhatsApp being mandatory for daily life ?

Even though I very much dislike WhatsApp, it does not require having full control over "your" device, and does not make itself an arbiter of what you can or cannot install on "your" hardware.

I can't see them changing this in the foreseeable future, major parts of their userbase run the cheapest phones one can buy, and they're much more interested in as much data as possible, so near 100% device coverage has to be important for them.

Last time I tried to use WhatsApp (in 2024), it was also basically unusable, because after I gave it the barest amount of information during installation (using its own dialog screens !), (in particular not willing to share my contacts), it regularly locked me out (IIRC as not a 'real' user).

Brazil is screwed beyond belief but WhatsApp being popular is the least of our problems. It's got enough end-to-end encryption to defeat judges. It's much better than some parallel universe where people are using SMS or Facebook Messenger or whatever. I'll count my blessings.