I would guess as technology gets more compact, so would real world weapons? Big and clunky is good for a visual medium though. It makes it look dangerous. You want a gun to look like it could make a hole in a tank rather than just remove a melanoma.
The gun that remove a melanoma seems like an elegant weapon, for more civilized universes
it reminds me of Star Trek
and how its creator dreamed of a utopia without wars, where everything can be handled through dialogue and diplomacy. Yes, that is far from being Star Wars
, Starship Troopers
, let alone the dark and grity universe of Alien
. I guess it depends of the fictional universe identity and what it's triying to tell to the audience.
Edit: Although it depends on the movie. For example, while Prometheus generates an in-universe tech anachronism, it was a scientific expedition.