It’s not quite a scam, but it’s generally unnecessary. What it is is a verification that it works well with the Switch. However it’s generally easy to find high quality MicroSD cards without that branding which will work just as well but cost less.
I wouldn’t go with the cheapest MicroSD card you find on Amazon, as that’s likely to be some offbrand of unknown quality. I would get a namebrand card that is actually being sold by that brand on Amazon. And make sure is a Class 10 card or has a UHS classification–those mean it will run at the full speed that Nintendo recommends, avoiding lag, slowdown, etc.
The trusted namebrand lists I’m finding include Lexar, Sandisk, Samsung, Sony, Kingston, and possibly Transcend.