we absolutely need desktopwallets aswell since myself for example don't trust anything that i do not have under my own control. I think others may think the same way. What's not on your own system (desktop wallet) is not really yours.
I wouldn't use any onlinesolution for storing coins. I think it's not safe. An onlinepage with login and password is like an invitation for hackers to brute force.

i am actually pretty excited about nem. Can't wait for release.