I must admit, I'm guilty of claiming to love learning new things, but only meaning things that I find interesting or expect to be good at. I think you raise a good point about being hindered by this attitude. It prevents me from mastering things that I do enjoy, as I always avoid the parts of tasks that I don't think I will succeed in.
Now I have to focus on learning things I don't like. I'm probably going to do it for the wrong reasons-- to better myself at things I do like, but still it's better than not doing it at all.
Is it the wrong reason though?
I would argue that the right reason would be more in the interest of learning for learnings sake, and the persuit of knowledge. Learning something to be better at something else may be a start, but it won't lead to as deep an understanding of the subject.