Define "worth it"??

For many, it's a hobby. For many more, it's an adjunct to whatever hobby they do have. Hobby's don't have to save you money; and I'm militantly opposed to monetizing hobbies as a way to "justify" them.

Personally, I'm mostly 3d printing custom components (that I've designed), for R/C aircraft of various sorts. (Like, my cyclogyros, or the flying saucer powered by a 3d printed ducted fan; which is, more or less, a scaled model of the saucer from the OG Day The Earth Stood Still. or the thermal airship using toaster wire that has taken on a lot of different forms, ranging from 20' star destroyers to whale sharks to a robot named Buoyant Bob that hands out candy on Halloween.)

I also enjoy 3d printing as a hobby, in of itself, too. (and spend waaayyyyy too much tinkering on the printer. its fun.) But it doesn't have to save me money, and I feel no need to compare it to other forms of hobbies. It's what I enjoy.

edit: lets put this in perspective. This would be like asking a golfer if they found golf worth it. the only real questions are "Do I enjoy it" and "can I afford it". not "can it save me a buck".