The reason the DSi appears, at launch, to be a wasted effort is that Nintendo launched the thing too damn quickly. It has twice the CPU speed and four times the RAM of the original/Lite, and enhanced/exclusive cartridges are a possibility (think GB to GBC), but none of that's ready and so that only leaves the mediocre online game selection for the foreseeable future, unless the sound/picture toys appeal to you.
and it's not above the D-Pad where you might try to press up just a liiiiittle too far and BAM, gone.
For the life of me I still can't imagine how anyone does this. My hands are gi-hugic (ring size of 14), and I've never had such an issue. Neither has the future Mrs., who is tiny, but before meeting me hadn't touched a game since Mario Kart 64.
You can also close the DSi while earphones are plugged in, and actually listen to the music, which is nice. The quality IS pretty bad, but then again, it's also being based off of the speakers in the first place, and I doubt you can force theater-quality surround sound into something the size of two DS games stacked on top of each other and the length of 1 and a 1/4 of a credit card.
Well, that's why we get decent quality ear phones.
I find it funny that people are surprised that the music works while the system is closed, though. Closing the DS is considered an input the same as the buttons and touch screen are, the system can do anything it wants in response to that. See previous games that search for other players while closed.
And of course, anyone with a flash card knows that Moonshell has had DSi music's ass kicked long before it was even conceived. If Nintendo insists on sticking with the AAC format, they could at least be friendly enough to point their customers to a decent converter. It really blows that they stopped supporting MP3, considering that's pretty much expected of any other music app on the face of the Earth.