I've gambled in the past, just to got games that I found completely not of my liking.
I can invest the same sum, for a discount game that I can choose that, at least, I'm interested too.
The fact is that, for each one game that the most wants, they put loads of game that have a low review score, to increase sales.
If they could publish a list of mystery game, at least, you could make an educated guess if gamble or not.