Why choose a new name when you can easily confuse people instead...
I suspect they're trying to distance themselves from the Kuro buttons, which have not been met with universal love. Everyone loves the Hayabusa joystick though, so they're making Hayabusa buttons to complement it. Brand synergy.
So what's the purpose of making the button height lower?
The machine translation of that article returned something about "quicker response." I don't know if I buy that on a button. We're talking about fractions of millimeters here if true.