Nevermind that the NDS and GBA are technically not the same device. The emulation drives the hardware, so especially for GBA titles which basically are ROMs in software, they should behave the same, right?
Nintendo Switch includes a microSD card slot that can be used to increase the storage capacity of your console memory. For example, if the memory of your memory card is 4GB and you have an 8GB microSD card inserted, the Switch's memory will only be able to use up to 4GB of that memory, leaving the rest for the microSD. This could cause some problems, such as not being able to save your progress or load an old save if the memory on the console becomes low. Hardware wise, I might have an SD card, but that's not entirely necessary. A Nintendo Switch will boot, even if it doesn't have an SD card. All the data is stored on the internal memory.
The NDS, GBA, GBA SP, DS, DS LL, 3DS, 3DS XL, and the Wii all use 16MB of internal memory for their games. The 2DS, 3DS LL and the Wii U use 32MB of internal memory. The first DS and the first GBA are also smaller in size, which may account for why some say the Nintendo Switch is too large for their liking. I'd expect the other four consoles to be similar to the other DS consoles, and the Mini to clearly be smaller; I doubt any of them will be as large as the Switch.
Now, some of these games are just old, but others added an SD card, specifically the DS and DS LL. With the 2DS, the console does not seem to have a slot and may simply utilize the SD card as a form of storage. The 3DS XL should look nearly identical to the 3DS. The Wii U on the other hand uses the SD card for storage, however.
This PSP version is being released as a digital download on the UMD for whatever reason. *EDIT, 3/5/13: The PSP version is not being released for the download platform, it's being released as a PlayStation Network download. The PSP version is actually being released physically on a URA-E SSD disk, like the Vita version. d2c66b5586