My thoughts on this? Well to be quite HONEST it's to prevent homebrew/pirating of sorts. That's just me though and you (Wiichat)?
source: mynintendonewsNintendo Japan has confirmed via its official website that downloaded Wii U software can not be saved to the SD card. If youíre looking to save software on something other than an SD card you will either need to use your limited Wii U internal storage space, or, invest in an external hard drive.
Downloaded software can only be played on the Wii U it was originally bought from. Meaning if you download a game to an external HDD and try to use that HDD on another Wii U, it wonít work. Downloaded software is saved to the internal memory or whatís in the USB slot. Downloaded software canít be saved to the SD card.
Hacking from a hard drive is really the same as hackin' from an SD card... 'Cept there's more space for more things, like damnable piracy. If they think that'l stop piracy, they're bein' idiots. Speakin' of, I'd bet money not bein' able to play downloaded software on another console will be hacked within a month of release lol.
No clue why they'd make it like this though. For SD-savvy gamers, that certainly is unfortunate news.