This is from MyNintendoNews.
New Super Mario Bros. 2 and Demon Training are the first Nintendo games that were released at both Japanese retailers and the Nintendo 3DS eShop. According to Nintendo president Satoru Iwata, in Japan, 5% of those who purchased New Super Mario Bros. 2 bought the downloadable version of the game, and 20% of Demon Training consumers downloaded the title from the Nintendo eShop.
Source
I thought this would happen, and the download takes about an hour anyways.
New Super Mario Bros. 2 and Demon Training are the first Nintendo games that were released at both Japanese retailers and the Nintendo 3DS eShop. According to Nintendo president Satoru Iwata, in Japan, 5% of those who purchased New Super Mario Bros. 2 bought the downloadable version of the game, and 20% of Demon Training consumers downloaded the title from the Nintendo eShop.
Source
I thought this would happen, and the download takes about an hour anyways.