With Nintendo moving most of their efforts into the Switch full-time, it's a little odd to log into the My Nintendo system and see that much of it is linked to the Wii U. It's been almost a year since the Switch launched, and it's high time they actually made the service somewhat useful for their current system.
Well, it's slow-going, but things are in the works. As announced by Nintendo UK, starting in "early March" you'll have the opportunity to spend Gold Points (read: premium currency you get from buying items) on Switch software. Although the exact details aren't live yet, the gist is that you can spend your points and then make up the difference with your account balance or credit card.
At the moment Gold Points are mainly just used on discount coupons, but Nintendo recently added the ability to get free games (mostly on 3DS) with them.
My Nintendo Gold Points [Nintendo]
via destructoid https://www.destructoid.com/nintendo-is-overhauling-my-nintendo-s-gold-points-to-work-on-switch-486815.phtml