Interesting but not surprised Nintendo would do that. I used to work on games a lot time ago and I know the general model hasn't changed. You still have most of the costs involved with the game if it's digital or not, but what is cut out is the packaging, printing(paper stuffs and the medium itself), and shipping. A digital game should go for around $5 if not a little more less but I guess if you can get away with it why not eh?
I see people arguing the benefit of digital over a real copy, and you're right, if you're lazy it's a boon as you just tap and play. The problem is, and especially with Nintendo and their childish backwater inane system of binding games to the hardware and not an account like Sony/MS do it a huge issue. Digital copies are just that, not real, and as such you're at the mercy of 'the system' the man or whatever you want to call it. Take a look at fairly recent history of Konami pulling Turtles games off digital download. If a company decides they've hosted a game long enough, or they don't want to re-up on paying for a license, or whatever other reasons the items get pulled. You then best pray you don't have a hardware failure, or how about if your system is outright stolen? Kiss all those hundreds of dollars or more in games goodbye. And even if they did have a system like PSN, eventually Sony would tire of keeping some 5-10 year old game up for sale and they'll erase it too, and if your hardware eats it, or you ran out of room but want to grab it again later...it's gone. With real media you have it until the piece of gaming storage(disc, card, cart) dies. I can go back and play a 1985 Super Mario Bros 1 game in 2012. Will I be able to come back and play my digital only copy of New SUper Mario Bros 2 in 2039 when I feel a nostalgia trip? Not a chance.
I've pretty much decided because I still have family in game making, that when in another decade they move towards going entirely digital I'm probably going to quit buying new gaming systems entirely. If I need a fix I'll have games from the NES through whatever to go through back libraries of tens of thousands of games to discover something new I missed. I'm not entirely anti-digital I'm good with the free and up to $15 type stuff, but I'm just not going to pay 'retail' values for a promise and a digital imprint.