No matter your interests. A 3D printer can be very useful. There are a lot of power tool/garage/storage accessories you can print.
A lot of stuff is just dumb, but there’s been times where I needed something that was really expensive online or couldn’t find it, but I was able to find the STL (3D file) online and had it printed and it worked quite well.
I’d say go for the A1 mini knowing it’s going to be a toy/hobby for both you and your son. Lord of beginner 3D videos on YouTube