On https://mov.im/?login it says:
"Login using any XMPP account or create a new one"
But it only shows me a login form where I can enter my xmpp address and a password. This signals to me that I can log into my existing non-movim-xmpp account, but I have to enter my password on there? That can't be right. What am I misunderstanding ?
This year I'm also going to be working on account access delegation for XMPP as part of a funded project, resulting in implementation in Prosody (server software) and publishing/updating related standards. That's the kind of thing Movim would be able to take advantage of so you can grant (restricted) account access to a remote Movim instance without sharing your password.
So that I can do something along the lines of "Log in with XMPP" and then my client asks me "hey do you wanna allow movim.eu to access foo/do bar on your behalf" ?
That sounds very useful. Sharing my password like this does not seem a great idea.
However it does not grant someone the ability to connect to your account and perform any actions. Movim is an XMPP client. It interacts with the XMPP network as you, not as a third-party. That's very different to what XEP-0070 is for.
Currently the only practical way to allow someone access to your XMPP account is to give them your credentials. But if you do that, there's no way to restrict, monitor or revoke their access (apart from changing your password - something they would also be able to do!).
Many XMPP server implementations already implement some of the building blocks for something better (e.g. Prosody and ejabberd both support OAuth in some form already). But there are a number of important missing pieces before we can get it usable and adopted, and that's what I will be focusing on this year.
Again, in Movim's case it's fully open-source. You can self-host it or run it on your laptop, so you're never forced to hand over your credentials to any third party today. But many people would find a mechanism to grant a third-party limited access to their account an acceptable solution, so they can use Movim instances hosted by others.