Thank you for your reply, @eleonorang .
Yes, functionalities is the adequate term. I have edited my post, thank you.
Well, you got me there. I thought you would say 40% top. I've heard many translators claiming to use or better, knowing how to use, only 20% to 40% of what their CAT-tool had to offer and that that was enough to work on the projects they have been assigned.
Just out of curiosity (if you find the time to answer), what are the other 25% functionalities that you don't use and why?