No reason to use SSDs unless they're trying to eliminate load times...but developers have gotten pretty good at hiding the slowness of optical media, especially on the PS3 where they can force a HDD install. Gamers have accepted loading screens as part of the process, so there's no reason to hugely increase the price of the console with a large SSD. A SSD/HDD hybrid drive may actually be a good idea for consoles - after the initial loading screen, it can load the rest of the game in the background to the SSD part to speed things up.