For me it would be a
huge improvement if this happened in my country. It would mean that if I'm sitting in front of a keyboard and a screen as I am most of the day, I would be able to reply to my friends comfortably using them. With that joke of an application called Whatsapp, I have to choose between replying from a tiny smartphone screen and on-screen keyboard, or going through a ludicrous ritual of photographing a QR code (which works only if my phone has wifi signal and enough battery).
To be honest, privacy in a general-purpose messaging app is the least of my concerns, as I have other means of sending important messages to select people. What is really annoying about Whatsapp is its extreme device dependence* which forces me to depend on a single device for casual chat with friends, family and acquaintances (and not the most comfortable use one) when multi-device messenger apps have been around for more than a decade. Telegram is like a return to sanity in this respect, so any news about Telegram invading Whatsapp's space are great news to me.
*I say "extreme" because Whatsapp doesn't even like if you switch your SIM card from one phone to another. It's insane. I used to have two phones (one for regular use and a cheap old one for activities where it could get damaged easily) and I had to give that up because Whatsapp would force me to re-register every time I made the swap.