backer board needed for kitchen backsplash?

My contractor has told me that there is no need to put backer board on the wall for a tile backsplash in the kitchen. During that discussion, we had talked about adding a 1/4" drywall layer over the plaster and then tiling it. (He recommended the 1/4" drywall over the plaster instead of ripping the plaster down.) The reason for the 1/4" drywall was because I have to pull off vinyl off of the wall on the lower half and when I pull it off some of the plaster comes with it. Now I am thinking that I would rather put up some bead board on the lower half rather than drywall the whole kitchen. Otherwise, the plaster is in perfect shape, no cracks, etc. Originally I wanted to gut it but he suggested the 1/4" drywall. I really would rather not lose the plaster because it helps to keep my house cool in the summer. My house was built in 1930. Help, before he arrives on the 15th! Thanks.