Honestly, I think Nintendo wanted to use this code - it would make sense for them to basically buy this if they wanted it and also wanted it exclusive to themselves. That's what I think is going on, but couldn't tell you why.
The archival goals stated are totally valid, and Nintendo continues to have a global impact on culture worth preserving.
It's crazy: growing up with the original NES as a child I wanted badly to know how that system worked, and then when NES emulators appeared in the 90's it was awesome that that was possible - and the whole emulation effort from the beginning was the product of people who just loved it that much. And also who wanted to play the cool Japanese games that never made it over stateside.
Looks like the Switch continues that tradition on. Nintendo will never ever escape this if it keeps creating these awesome characters and games. The love for the games is just too strong.
I wouldn't be surprised if they wanted it to make their own game streaming service like Nvidia.