On the one hand I’m sure this is just because they’re not paying for api access, and it’s not Nintendo’s fault that Twitter started charging for it. On the other hand, the user experience for sharing screenshots is terrible. I’ve never been able to get the QR thing working on my phone. Your entire screenshot gallery should be available to you on the web, period. And I will note that Sony’s experience is only just barely better than nintendo’s, and only very recently too.