> Thing is, this better be a really important case. Because if users migrate and stay on Telegram, it could be much harder for Brazilian courts to get records in the future.
Why would it be harder? Telegram has the entire plaintext message history for every message all of their users have ever sent, WhatsApp doesn't. It's much easier for Telegram to comply, not harder.
I'm not completely familiar with data storage and access policies between the two, but I was under the impression that Telegram's main selling point was security/privacy and that you could schedule messages to be permanently deleted from Telegram's servers. Now that I've read more on the subject from you and others, it seems to be UX/UI and marketing.
I'll defer to you on this one as you're an expert in the field.
Why would it be harder? Telegram has the entire plaintext message history for every message all of their users have ever sent, WhatsApp doesn't. It's much easier for Telegram to comply, not harder.