I am so confused. I think it matters... Just when I think I'm "getting it" about skilling and skills, somebody (you in this case) says something to make me go "tilt". Here I am skilling my brains out with my 1x0 Axe to build up my Melee skills, and then I see your remark that you selling "useless" Melee skills - the ones I'm spending peds to increase. So that makes me question why one would sell skills that are so hard to get? Then I question, why would I continue to do it if they are useless.
When you say they are useless to you, I guess that means you are focusing on something else - like rifle - that does not require a high level of Melee skill. Is that a correct assumption? If so, then I understand what you meant and I don't fell like I'm wasting my time.