I refer to hobbies when talking about how my DP spends his time, to underline the fact that he does these things because he enjoys them, though he claims it's done to benefit the whole family. He reckons my pastimes aren't productive, so they are just hobbies. I get nowhere near as much hobby time as he does. If I named his hobbies without identifying them as hobbies, you lot might side with him instead of me.
Examples: He keeps chickens. Nobody else in the family is fond of chickens. Yes, they give us eggs, but he spends more money on chicken food than we save on eggs. They are pets, not livestock. This is a hobby. Even when he is cleaning them out, or driving to the other side of the county to buy cheap chicken food, or fixing the broken chicken house, he is doing his hobby, not "work".
Same with the allotment. I'm sure the veg is nicer than what we'd buy at Tesco, but honestly I would be happy enough with Tesco veg.
Beekeeping. They've never thrived well enough to give us any honey. Keeping bees is good for the environment and all, but it is still a hobby.
Going round the car boot sales, buying broken machinery, fixing it up and usually giving it to friends. Or using it for the hobbies above. It's lovely of him. It is a hobby.
200 years ago all this stuff would have been of economic value to our household. Now it is just a bit of fun. So yes, on MN I wouldn't say exactly what my DP was up to, just "doing his hobby".
For the record, my hobbies are chess and reading. I don't pretend they are anything other than amusement.