I thought the Flash Memory was a little more durable than that...

In any case, it's a much longer-lasting type of save state than the battery backup of old. All GBA and DS games use flash memory for saving, so you don't have to worry about battery life or anything.

On a side note, something that ticks me off is that G/S/C was released in 2000/01 with battery backup in them, and the GBA was released in 01, with even the first games made for it using flash memory. They couldn't have given us a taste of the new technology?