It's been mentioned that there is a good deal of industrial usage for this tech. Polymer gun parts can be made from it and working AR lowers are being made. There will be improvement.
But a part of a gun isn't a gun. The law currently allows a person to build a gun in their home, without a serial number, if it is for their personal use, though various local jurisdictions may frown on that in various ways.
More interesting is the ability to produce a working model of a gun (or anything else for that matter) for experimental and design purposes. Or your own air soft gun. There are possibilities for the teams working together on designs to build working models.
Some folk believe the tech will somehow "empower" people. I don't see that happening except in the way that the home sewing machine
"empowered" some to make their own clothes at home from patterns ordered through the mail or bought at craft stores. Some also used the portable sewing machine to teach themselves to design clothes in hopes of being the next Versace.
But many millions more were "empowered" to work for piece work wages in garages and sweat shops. There is potential here for these machines as well in the production of widgets for industry.
3D printers are going to become more and more prominent as technology improves. They're already working on models that can print metal and (more interestingly, IMO) living cells/flesh.
The "adult entertainment" industry will love these things. So will the home "hobbyist".
Personally I can't wait for the day when there's a 3D printer in every home.
Brett Favre will have some fun.
More seriously a small cottage industry in revolver and pistol grips could develop. Custom grips fitted to your hand for a few bucks.
Not everyone will want one of these sitting in their bedrooms.