So, how is this any different than those blessed with beautiful voices? Using your logic, the person with the beautiful voice should only sing for free to give pleasure to others. Sorry. That's just not the way people work. Anyone who records and sells music is making money from their gift.
I find it hard to believe that if you had a gift and someone offered to pay you large amounts of money to make use of that gift, that you would turn it down. I wish I was an amazing artist or an incredible writer. I'd be selling my work for big bucks and totally taking advantage of my gift. The only difference between these gifts and a psychic gift is that the vocal and artistic gifts are definitive in nature and the psychic gift is not.