One of the draws of the Expansion Pack isn’t just the ability to play classic N64 games on Switch. It’s also the chance to play them online, something that wasn’t an option before. But players have similarly been encountering a bunch of frame rate and latency issues while trying to race against friends.
While there are some rare exceptions, the way you can watch the highest quality of a movie is to buy it from the company who owns that movie. If you want the best version of a written novel, buy the physical book for the best construction or buy the official audiobook to get the best production quality. But to play the best version of a video game…that gets more complicated.
When it comes to new games, it's always best to buy the game as directly as possible from the publisher. That said, once time marches on and games no longer run on the latest hardware, things get tricky. The Nintendo Switch has been out for almost 5 years and in that time owners have not had a way to play any old Nintendo 64 games at all. Now they're here and they pale in comparison to the experiences you can get from using an open source emulator on your PC and loading up your favorite ROMs. Is it legal? Depends, but often technically no.
I think video game preservation is an important thing and it's still far too difficult to play great versions of the best games ever made. Far too often you literally can't even play them if you wanted because no one will sell you a legal way to do it, and I really hope that changes.