I believe it is just "as of" the XKCD comic, for which "aperiodic table" seems more sensible than "quasiperiodic table" for how the comic was written. The exciting thing about using the Penrose tiling is that you get "aperiodic" without it just being completely arbitrary. For that it is natural to borrow XKCD's terminology for this particular project.

I don't think mathematicians are going to change their term to "aperiodic". Almost everything is aperiodic. Quasiperiodic indicates something much more interesting is happening.