People get paid for all sorts of reasons. If you are being paid specifically to put work in front of your hobbies, then that is your job! Think database uptime employees who are paid to get up in the middle of the night to fix a bug, etc. Heck, I even paid a friend to eat a shoe once; you can pay people to do all sorts of things. Paying someone to put work in front of hobbies is hardly novel or extreme.
Of course, this should be clear in the job description!!