If there was a criticism to be made regarding the Wii U or 3DS, it is that in a world of cloud computing, for some reason games purchased would be linked to hardware instead of your account. This means that if you buy a new hardware you’d have to transfer your purchases which can be rather troublesome.
The good news is that this no longer seems to be a problem with the Nintendo Switch. It has been noticed that Switch Eshop Purchases are now linked to the user’s account. This was spotted in a recent video of someone unboxing their Switch unit 2 weeks early (which was apparently a stolen unit). During the setup process a message was shown that confirmed this.
The message reads, “Your Nintendo Account contains your Nintendo eShop purchase history and current balance. By re-linking your Nintendo Account after initializing the console, it will be possible to redownload any software or DLC purchased using that account. (Software that has been discontinued may not be available for redownload in some cases.)”