I had the same curiosity and concern, so I bought one (in the name of science, obviously).

I've now had it for about half a year, and it is in fact tons of fun still.

There are some supplementary activities/hobbies that help:

• Electronics (holy fuck, I hope my SO doesn't find out how much money I've spent on digikey.com)
• 3d design (doesn't have to be anything fancy. I do most of my stuff in blender, and I consider myself a beginner).
• Minifig painting (not me, but I'm sure some with 3d printers find that useful)

My printer is in use almost daily. I'm currently printing a bicycle pump mounting bracket that I can screw onto the wall, because I'm fed up with having to figure out where the fuck the bicycle pump is every fucking spring. Took me 10 minutes of cobbling together a design in blender.

I bought one mostly just to have a new toy. But it has become an essential tool in my household.

I mostly print functional stuff, but I also use it a lot for my electronics-projects, which does happen to include an RC project that I hope to see fly this summer, budget permitting.