All that says is that Sony didn't choose the medium for the system wisely. Handheld gaming devices need to be suitable for short bursts of gaming on the go. Optical media of any kind is ill-suited to that for multiple reasons. For one, all of the time spent loading is time not spent playing, and the window of time available to the player to be playing and not doing whatever he or she is out and about for may be very limited. It's also time that's still spent draining the battery. Not only that, but the battery actually drains significantly faster while the disk is being read. There's a reason that PDAs use solid state media instead of something like Sony's UMD.
Sony chose the UMD because they wanted to make the most "tricked out" portable, and because they were hoping to launch the UMD into popularity and use it in a number of other devices (hence the name "Universal Media Disk"

. Neither of these are at all in the interest of gaming, but rather a way of trying to use a gaming device to advance their interests in other markets.