I have it show both the pinyin, the chinese characters, and the english (3 separate lines). Yes, I hover over unknown words to learn them.
There's a few features missing that I wish it had: 1) sometimes it groups characters wrong and I can't ungroup them, so then I have to manually use pleco to look them up and 2) it doesn't allow you to look up individual characters in words to find the "sub meanings" (again pleco fills this gap). The first problem is really a "mandarin-only" issue and people's names cause most of the problems (sometimes it thinks part of a person's name is instead of part of an adjacent word).
Yeah I think it is a Mandarin only issue, is it because of how the language merges words/characters into one? I can do all of the things you mentioned with French, look up individual words, and check their sub-meanings, as well as the root of the verb.
Yes, its not a problem for languages with word breaks. It's not a big problem even for mandarin, but it occasionally makes mistakes. I just wish it had a way for us to override when it does.