unless there is something else involved, like a mario competition or anything else that could add productivity, i would say it is slightly more productive coming on here because it allows you to practice typing, which is useful in a variety of situations. pretty much any other minor benifits such as coordination improvements or finger excercise are likely to be comparable in each...
the question wasn't about fun, it was about productivity. although i agree, mario is funner than this (although it also gets old faster)
do you hope to have a future as a professional gamer? you could always work towards beating the world record, I saw a vid of a dude who beat it in about 11 minutes. if you can beat that, you could get your name out there.