Can Gold Points earned on Nintendo Switch, Nintendo 3DS or Wii U be used on a different device from the one they were earned on?

Yes, Gold Points are interchangeable. They are not restricted to Nintendo Switch, Nintendo 3DS or Wii U, regardless of how they were earned.

For example, if you earn 100 Gold Points for a Nintendo 3DS game purchase, you can spend those points on a Nintendo Switch game purchase on Nintendo eShop.