yachi isn't the one saying "don't bother"
I don't mean it in that way.
I mean:
has he created any themes/skins in the past?
If he hasn't, how will he manage to co-op by making a skin now, when he as no experience in making skins. Sure you might say, he can always learn. But that depends on his knowledge on coding programs.
I my self, categorize my sense of knowledge. Things I don't know, I don't want to experience or learn it, as long as I know it works. Things that fall in my knowledge, I tend to know more about it.
Sure as...
fashion...I am an computer specialist, I study I.T. I know nothing about fashion, if I want to learn it. I will find it difficult.
Me and Yachi are different and we progress strong and weakness wills.
I am good at making websites, editing movies etc.
Yachi is excellent at flash!
If I tried to learn flash, I will fail! and I have used it before, but found it too difficult.
Anyway
as Kratos normally says "do what you will!"
you might be better at designing icons or pictures. than doing the coding bits