My only take on this is, I agree with the OP that it looks dumb in a lot of the Gifs posted, but looks fine in a few to.
I'm sure it's fun though (for the one dishing it).
My preference would be for games pushing for a more realistic aesthetics, the over the top juggling (vertical push for regular hits), but for hits that make sense for real physics, like kee's and uppercuts, sure that can add to some kind of juggle. I like it becuase it makes the player choose their hits carefully if they want to maximize the juggle.
And yeah, many are confusing regular combos, and air combos with juggling.