Which is better: playing chess as a hobby, or playing in professionally??

If you play professionally, you are really good, but your pay and life relies on how you play.

If you play as a hobby, you don't get paid, actually in some you do, but your life doesn't rely on your play. Also, you don't (generally) play as good.

As a professional musician, I can say that there are huge difference between doing it as a hobby and doing it for a living. I have to devote a huge amount of time into my various music projects and constantly practice. If you shows are bad, no one wants to see you. You also spend countless hours in the studio, etc. Of course, the rewards are like winning the lottery. I put a lot of time into my chess and I couldn't image putting seven days a week, 8-10 hours a day into it because of the mental stress.

There are far many differences than listed in the OP, such as time difference.

I think that it depends on whether or not you have the skill and love for chess that makes the difference between a pro and an amateur.

There are few, save the elite chess few, that exist solely off of tournament income. A good majority of professional players get their income from a secondary profession or from other aspects of chess like teaching events like paid lectures, lessons, and camps. As far as your question on which is 'better', playing amateur or professional, this again is one of those subjective, unanswerable questions. 'Better' is a unique idea to each individual person. Your question sounds to me like you want to find out which is more monetarily lucrative, playing as an ametuer or as a professional, which is a much more measureable and answerable question than the 'better' query.

Natalia Pogonina is a declared professional.  A GM with an FIDE rating of 2500+.

Why not ask her what she thinks?

Obviously people need the talent first, and the love of the game second.