i used their iOS app, and they seem to have an outage around once every two weeks. other than that the performance is fine. it must be a front end problem
I have until now just assumed they want the website to suck so that you are more likely to install the APP. But now as I think about it a bit deeper that seams a bit to crazy.
I'd bet there's some super frustrated PM/TL who knows what to do and wants to fix it but isn't allowed to spend any time on it.