Everyone else's hobby seems like an expensive waste of time. I quilt. It's expensive and time consuming, but I love it so I do it. I'd do it even if the quilts just sat in my closet.
A friend of mine travels all over creation collecting toy tractors. He has thousands of dollars in them. It sure looks like a waste of time and money (better spent on fabric) to me, but he loves it.
I've quit trying to justify it. I do it because I love it and I try not to comment on other hobbies that I don't understand.