Even if this is by design, the current way the "as needed" option work, if you set all locations and projects to "as needed" in your account settings, it doesn't work properly.

I did this, and got BOINC Central and Denis@Home, both of which didn't have any WU's currently available.

And then hit the Syncronize button, and got PrimeGrid, which of course always have WU's available.

But still, why does the account manager behave liked this?

I'm getting this a lot too. And a lot of "Invalid or missing account keys, to fix, remove and add the project" and you can't remove a project chosen by a manager. Reset doesn't do anything.