To draw a comparison with the Wizarding World, I knew nothing of Harry Potter (never read the books or saw the films) before stepping into the land for the first time. It's still an amazing feat that was pulled off in building the land, and there is tons of detail in there for the die-hard fans or newcomers alike. I've witnessed people burst into tears while entering the land for the first time, which speaks to the power of the IP and people's connection with it.
Nintendo is going to have the same effect. It's a showpiece for the park. They're pushing interactivity with the land, which has been toyed with in the past, but never integrated this deep before. The land is already gotten coverage outside the theme park sphere, and is going to attract an audience who may not have interest in other lands. Parks are better off for being diverse with their offerings, and Nintendo will only broaden the appeal.