I think it will depend on the person, his personal situation and where you live. If you spend a lot of time a day and get enough income to live exclusively from that, it can be considered a job but if you do it sporadically and only get an additional income or none, it could be said a hobby. In any case, it would be like having an unstable job without guarantee of obtaining enough income to live and it can not be compared with the stability of receiving a salary every month and having a legal protection from a conventional job.