Would you change your rules if your kids showed interest in developing actual computer skills? My parents had rules similar to yours and wouldn't budge, and it effectively killed a decade of potential programming experience. I still resent them for it to a point, but I realize they were just ignorant and thought learning to program was equivalent to playing, because I was at the age they thought I was supposed to be playing.

Just... try to avoid making your kids be something they're not, in general.