Nintendo Support: Discontinuation of X (formerly Twitter) Integration and Social Media Integration for the Friend Suggestions Feature on Nintendo Switch
In a roundabout way, you could argue both were factors.
Twitter’s echo chamber becoming cacophonous with spite and worse means less people visiting the site, and refusal to support the site would be a better look, but that pr move might be easier on the corporate wallet as well.
Twitter integration was incredibly ubiquitous in all social based tech for some reason. I'm assuming its API was originally very friendly and unintrusive and now it's probably the exact opposite. I think X is now also charging money, which is likely the primary reason Sony and Nintendo are dropping it.
I'm assuming its API was originally very friendly and unintrusive
Which would make sense - stuff like this automates content creation on your platform, which justifies pricing for advertisement (its main income). Basically bots but not really because they're initiated by a human action.
Other than ejecting your microsd and having a reader for it, it used to be the only way to get screenshots off of your console. That's the only reason I have a twitter account at all. After an update several years back you can just send the images to your phone.
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.
You used to have to post images to social media to post them to splatoon 3, now it will just bypass social media completely. Sadly they didn't do the same for Splatoon 2, so now you won't be able to post things in Splatoon 2 :(