The problem with making value a defining characteristic is that it is subjective.  Something can have value to me, but to no one else.  Take your example, if no one bought your reaylscoins they could still be very valuable to you.  They represent time and effort you put into creating the fork and even have sentimental value.  

We can also see this with collectibles.  Have you ever seen the phrase, "I USED TO BE A MILLIONAIRE UNTIL MY MOM THREW OUT MY BASEBALL CARDS".  Well, to the mother that threw them out, they had no value.