I buy salted butter for 2 reasons:
1. I don't know where you buy your butter, but where I buy mine, salted butter is about 40 cents cheaper per pound
2. I keep my butter dish in a cupboard, so I appreciate the extra storage time, even though I have never needed it
Pat for pat, no matter how you use it, the butter, and whatever you use it in or on, is going to taste exactly the same to anyone except to my mother, who is capable of smelling fly dung across a six lane highway, upwind.