I only said am not very good at either - but competent enough at both to do them professionally, I think (and I have). Only trying to be humble ;) Anyways - Like the comment below, I don't believe anyone should be "forced" to do something, but at the same time no one should be closed-minded about learning new things.

The one thing I have learned from working in both areas is that in the beginning you improve very rapidly, but at some point only hard work drives you closer to perfection. I would advise anyone with an open mind to at least try learning something they are not good at. Not a requirement by any means, but I do not think anyone would regret trying.