Nonsense. I'm neither technically nor artistically top of the bill, I have no good clue about the "capabilities of modern computing", but still I've been an active demoscener (producing and consuming) for years. To say I don't understand why these things are impressive is, well, a bit weird.
For me, it's simply (and only) freeing yourself of the limits of <your favourite animation tool> and replacing that by the limits of your programming skill and your computer's raw power.
This differs per person, but in the winning Assembly demo shown at the OP, for instance, some people may find the sea-particle-system impressive for its technological prowess; i'm more impressed by how code, not keyframes, was used to choose where which wave flows.
This also implies that I can find the same awe in watching Processing sketches, even though those hardly ever push the hardware limits.
For me, it's simply (and only) freeing yourself of the limits of <your favourite animation tool> and replacing that by the limits of your programming skill and your computer's raw power.
This differs per person, but in the winning Assembly demo shown at the OP, for instance, some people may find the sea-particle-system impressive for its technological prowess; i'm more impressed by how code, not keyframes, was used to choose where which wave flows.
This also implies that I can find the same awe in watching Processing sketches, even though those hardly ever push the hardware limits.