Passion is a flame best kept in a controlled state.

 While everyone and their mum will entertain the idea of turning their passion/hobbies into a job, the feeling is fleeting.

One may enjoy your passion/hobby job for a few months or less. They'd find out eventually that the prospect is not as colourful as it seems. They could be an artist struggling to find anyone who'd give money for commissions in an ocean of artists in the same boat as them. They could be an indie game developer struggling to find a player base that would stay consistent for at least 3 months and maybe spend money on that game. And they will also be competing against thousands of other indie game devs with the same game idea they had. It does not improve when one is working in a company either. They can have their passion/hobby to help them get a position. But at the end of it, they will have to be consistent and sharp 24/7 lest someone else much more "talented", for the lack of a better word, will surpass them or worse give their company an excuse to lay them off. As the saying goes, "the brightest flame burns out the quickest. Passion and hobbies, being the bright flames that they are... I'd rather keep the flame just right so that I am able to appreciate it on what it's supposed to be, the flame where I relax and sleep next to. If I ever utilize this flame for a job, I'd have to keep it brighter than most in order for it to break even. And if I do that, I'd have no time to savour the comfort and warmth of the flame. The world will have turned it into a part of a machine. I'll never get to relax. I'll never feel its comfort, the best fuel requires a lot of effort to procure.

So I'll make a flame separate from this personal flame of mine. For in case when I somehow burn out from a job, I shall have my personal flame to comfort me and I shall never have to suffer through the cold dark winter.