I can't write music either and don't claim to, but when I play something, to me it is REAL music from my heart. I just need help to be able to do that.
So while not everybody needs this, some of us really do!
I will never say no to learning anything..knowledge is power. Though I envy those to whom it comes naturally I will never be one of those people and music makes me feel good. That is all that matters to me.
So in a nut shell...theory is necessary for some of us to make sense of it all!