This is pretty common in the whirlpool business. (BTW, all images on Google for 'komforttaster' come from Whirlpooltechnik.de.) You're quite right -- comfort isn't in the phrase, but it is indeed what the pool is all about, so perhaps it would be a redundant term for the buttons. What else would the buttons control if not 'comfort' levels, by adjusting speed of current, temperature, etc? And you couldn't say 'key'pad because the controls don't open/close, lock/unlock anything; or rather, that's not their primary function.