The info convention from Sins was useful in large part because the information wasn't available in the same way anywhere else, but right now the information in the info card is exactly the same as the info you'd get from clicking on the unit. It seems redundant to do both.
The point of infocards is to make information available without requiring you to actually select the object of interest. If you have something selected already and you are considering performing an action that is dependent on some other information, it is nice to be able to retrieve that information without having to click on everything and its mother, then fumbling your way back to whatever you had selected originally to actually carry out your action.
Basically, infocards are there to provide information about things that you don't have selected so that you don't have to select it and change your focus. It's a huge time saver and it will help stave off carpel tunnel syndrome for a few extra years