Well the same thing applies, only it's even harder to mash two buttons at the same time. That would also make multiple dodges a bit harder. Well, they should have just done that instead.
Yea, also the fact samus jump / flips out the way makes jump seem like it's needed for a dodge move.
and because it's two buttons and harder to mash together = less incentive to rely on it all the time
and because it's two buttons and harder to mash together = less incentive to rely on it all the time