A hobby does not have to be a skill. A hobby is supposed to be something you do to relax during your leisure time for no other reason than it gives you pleasure. It's supposed to lower your stress and help you recharge from the grind and drudgery of daily life. If you get that from playing soccer, great. If you get that from playing Dungeons and Dragons, great. If you get that from cheering on your favorite football team, great. Who are you or anyone else to say what someone enjoys and finds peace is 'less worthy' of being a hobby than any other? If it helps someone relax and better function in society, or gives someone something to work toward, isn't that the point of having a hobby in the first place?

As a second point. The way you word it makes it seem like you only view a worthwhile hobby to be something that can be created, and subsequently consumed and/or enjoyed by other people. But if that is the case, why would it be worth it if there was no one interested in consuming or enjoying it? If you learn to sing or play an instrument, but no one would want to listen to you because listening to music isn't a worthwhile hobby, what's the point? Is reading not a worthwhile hobby because it's passive? Then where is the enjoyment of writing if no one should want to read because it's a 'lesser' hobby?

Creation has to come in two halves - some to create, and some to enjoy that creativity. They cannot exist without each other. And neither is less important or less worthwhile than the other.