Hey Kharthynogus, it's always nice to see new ideas on the forums!
I suppose you've got a bit of a point, but...
After hearing you out, I am going to refer you to the authenticity vs realism debate.
Muse works pretty hard to keep the guns balanced, and having greased rounds serve in the roll they do is more important than the rounds behaving as if they were actually greased. Remember this is a fantasy world, not an extension of reality. If you are willing to accept the complete re-writing of physics to allow the boats to fly in the first place (these ships and the way they fly are pretty much entirely impossible) then why not accept that the ammo types are just interesting names for certain functions?
Muse is more concerned about making the game fun than they are trying to keep it real. I'm no munitions expert, but I think heatsink clip would actually raise the rate of fire on some weapon (like the gat) by keeping the barrels cooler. Point being, it's sort of pointless to attempt to apply physics or realism to anything in the game. The two questions that need to be asked are: 1) Is it fun? and 2) Is it balanced?
(Honestly, if it were realistic, long range weapons would be the be all end all, and once your balloon was out, it'd be all she wrote. I'd worry less about realism, and from a gameplay perspective, I think greased plays a very important and distinct role.)