I've certainly used this with a Firebolt yesterday, not sure if it functions for spells that don't have an attack roll, as I haven't used one in that way. Note that you aren't given proper feedback, such as a targeting reticle, when doing it this way in my experience, so the ability to do so my be unapparent.
I just had a play around, and clicking on a portrait at the left or in the combat queue works for attacks, bottle throws, healing spells and AoE effects (centred on the selected character) but seems more hit & miss for cone effects.
And while it puts a highlight around the sprite of the targeted creature so you can see which is which, and also seems to represent any movement that would be needed in order to carry out the action, I agree it doesn't show the % chance to hit or text confirming what action is being taken, unlike hovering over the sprite with the action or spell selected would do. I'm not sure whether it always was like that or if it's a new bug, but either way that could certainly be improved.
Still, fortunately this looks like something that is at least partially implemented, even if it needs some tweaks to make it work really well.