You have to understand what bitcoin really is. It's not a type of job but its a the "crypto"currency that you will receive once you did a job well done.
Bitcoin can still be considered as the main job for those who are really passionate and knowledgeable about bitcoin.
Trading can be a main job but again as I've said, you have to understand what bitcoin is and that's not a job. It's a medium of payment which can eventually turn into an investment.