I've never used alum block, and I've been a daily wet shaver since 1951.
I guess the reason I've not used it is I've never felt the need for it. I also belong to the "if it's not broke, don't fix it" club.
Never felt the need to use it either. I don't have facial irritation. Always thought that aftershave was intended to be used at the conclusion of the shave? I am fine with that.