It's still impressive, though. It's not as if Facebook's chat works this well and that isn't (wasn't?) encrypted either and they've got an even bigger pile of cash. It's also a lot older though, just look at the evolution from IRC to MSN to Facebook to Telegram: each step it gets better. Maybe that's how that difference can be explained? Anyway, between normal messengers like Signal/Whatsapp/Wire/etc. and Telegram, the main difference is not caring about privacy. (To be clear, I don't mean that whatsapp is a privacy-conscious messenger as they will collect what they want behind the scenes, but on the client side they have to care about keeping the server "untrusted" and that will slow everything down a lot.)