Nintendo going mobile was NOT their most important announcement.

[Soundwave]

Nintendo going mobile is basically part of its own merits ... Nintendo simply stands to make a ton of money by doing so.

I think it really is just that simple.

If a few more kids decide to buy a Nintendo dedicated portable or console as a result, that's just icing on the cake, but it's not the cake itself.

In a couple of years it's quite possible mobile games will be the no.1 money maker for Nintendo, they need DeNA to keep those games running, Iwata has said they're aiming to leverage their existing IP into several smartphone titles that are big hits.

I tend to be cautious about getting overly grandoise about things like Nintendo's online services ... remember when people were touting Miiverse as some kind of huge game changer? Lets be real, even if there is a service like the one outlined in the OP, "being as important to someone as their Facebook or Twitter app" is a massive, massive reach.

Game sharing, unified network ID is something Sony has been doing for ages, this is more like Nintendo (as per usual) being about 8-9 years late to that party.