so evidently normal guns exist in star wars (called “slugthrowers” because of course) and they’re apparently super broken and extremely useful because they go right through shields designed to deflect energy weapons and if a jedi tries to deflect them with a lightsaber the bullet just melts and turns in to an equally lethal spray of molten metal 

imagine you’re the most badass sith in the universe and Some Dude With A Handgun challenges you and you’re just like “heh… primitive weapons… bring it on” and he shoots you and you suddenly get splattered with a shower of molten metal and you fucking Die 

So, you know why science fiction has people using laser weapons? I mean, other than them being all cool and science-y, I mean?

So, a lot of science fiction, especially back in the day, takes place in space–on space stations, spaceships, that kind of thing. Places where you really, really don’t want to go around accidentally poking holes in things like, say, the walls.

And you know what firearms are really, really good at? Making holes in things.

Now, lasers are also good at burning holes in things–but they have an interesting drawback. See, when you hit something with a bullet, you make your hole by pushing the matter you struck in and sideways. When you hit something with a laser, you make your hole by heating the matter very quickly, making it evaporate. Things tend to expand when they evaporate–you create a puff of Stuff Particles that (and this is important), goes out and sideways. Right into the path of the laser, partially blocking the beam. You can still drill your hole, but it’ll be less efficient.

Solution: fire the laser in pulses instead of one solid beam, giving the vaporized Whatever time to clear out before the next pulse hit. Of course, how long it takes the Whatever to clear depends partially on the strength of the laser and partially on the substance you’re shooting it at–but that’s okay, you just give the laser different settings for shooting different substances.

In other words, it’s entirely plausible for a laser pistol to have a setting that makes holes in people very efficiently, but isn’t very good at making holes in metal at all–exactly what you want the security officers on your spaceship to be using.

(None of this has to do with Star Wars, of course, because Star Wars is the point where everyone realized that science fiction really is just fantasy with a robots-and-spaceships skin applied, but it’s why hard SF stories from the first half of the 20th century had people using laser pistols, and ultimately that’s why laser pistols became part of that skin.)

And, at least for the ships, ostensibly the speed difference was significant. Ammunition, also.

Oh yeah, for ship-to-ship fire the advantages of lasers are (1) they’re much much MUCH faster than anything you could fire out of a cannon, (2) they have RIDICULOUS range and accuracy (not that this matters in most TV and movies, since those usually have space battles occurring at distances comparable to trying to punch someone while you’re standing on their toes), and (3) you don’t have to carry ammunition for them, making your ship that much lighter and thereby making more room for fuel.