An interesting question to say the least.
25+ Years ago I quit smoking and took up sewing - as a hobby because I still worked full time. Over the course of time I started selling many of the stuffed animals and fabric items in local craft shows. Then in the past 6 years it's become more quilting than just sewing - a dear friend dragged me to my first quilter's guild meeting where they were doing landscape quilting, met some amazing people, enjoyed show n tell and was hooked. Sewing still relaxs me, allows me to talk to God in my own way and since my hubby retired gives us additional income to enjoy life and traveling more. I sew for 1/2 hr before I go to work, cut up things to be sewn during my lunch hour and sew for at least 2 hours in the evening. Then becasue I only work 4 days out of the week we either go on adventure, do a craft show or stay home doing chores and sewing. It take hand sewing & hand quilting when we travel. Thinking this all out I'd say for me it's not so much a hobby as a wonderful obsession with benefits.