I have one (my third over the past ten years) and have used it to make all kinds of things. Hooks for the shower, pool scooper hanger, some inventions of my own, (etc, etc)... and plenty of gun parts. The AR grips I’ve made have been junk but the AFGs and ammo boxes were spot on. I haven’t made any reloading tools but I’ve only got a single stage press and all the tools I need.
IMHO, every home will have a 3D printer in the not-too-distant-future. I can see a time when you will scan your feet, upload that into your computer, go to the New Balance website, select your shoes - color, material, closures, tread pattern (even custom ones) - and then print them to fit your feet exactly (just as one of many, many examples). 3D printers will become as ubiquitous as microwaves and lasers.
PS For those of you who think they are too expensive, yes they can get pricey but you can get a perfectly usable Ender3 for less than $200. I think I saw one on Amazon for $180 a month or so ago. My Craftbot cost me $1,000 three years ago and it’s still working like it was new.