I like toast and hot food in general so I've got nothing against toasting banana bread, but honestly, I've never thought to do it. Personally I like it cold without butter, good banana bread can be enjoyed without anything extra IMO. Especially when it's a really soft banana bread that just melts in your mouth without any extra heat needed. I should try toasting it next time (it's rare I even eat it) and I may really like it that way better.