Using a QR to facilitate login is not a bad decision. Having this as the only method to authenticate makes it a bad client because it can't work as a standalone offering.
I don't like when "web clients" are not full featured in the sense of allowing registration and login. Look at Evernotes, you can register and use thru the web client interface, there is no need for the app if you're on a platform that is not supported.
EDIT: If you feel the need to use cutesy graphics to get your point across, at least make them static. Animated gifs are incredibly distracting when trying to read anything more involved than a tweet, or a silly meme macro.
Frankly, I hope those apps will all be gone and forgotten in favor of an actual open sourced, widely used protocol. Or maybe they'd incorporate one. But in any case, I think it's a shame that when email is decentralized, chatting is not.