To be fair, I think that part of the whole reason that Microsoft converted cash into "not-really-cash" was to avoid some particular rules that the government imposes on cash transactions. I forget offhand exactly what they were, and obviously Sony cracked that nut a few years ago, but I believe there was some sort of issue figuring out tax and a bunch of other stuff when people used cash. So, they decided to transfer them to points that weren't exactly cash to work around that.

Since Sony cracked it, they have no real reason to keep it the exact same. As for the brain research, I wonder if they would sell more as 800 points or $7.99. To me, $7.99 seems cheaper than 800 points. My brain does the opposite when I do those cards, and I always assume I'm paying MORE for things than I am.