I think this is a fair question.
Yes, I know most electronic musicians will have a MIDI interface already. However, I for one don't like having my table full of ugly little(?) boxes each for a single purpose, specially as each box usually means at least two more cables.
One of the myriad reasons why I love my A4 is that you can totally use it without any other box around, and if you want to connect it to your DAW, that's just one cable. So it seems Elektron "gets" this kind of thing, thus I think it's reasonable to consider the Heat could also work as a MIDI interface. If it did, it could replace a lot of boxes and cables on the average electronic musician's desk