I can see the anti-let's play argument being made for heavily narrative driven games, but I don't think Nintendo has many of those so I don't think it really works as an excuse to them.
Just seems like a case of Nintendo being behind the times and doing something not so consumer friendly because of it. Many youtubers won't even bother and they'll only be left with the nintendo apologists which I guess you could view as a benefit for them if you think that public opinion needs to be managed in this way, but overall a detriment to their image that I think far outweighs whatever benefits they will get.
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