I would like to remark upfront that the bulk of my post was about the equally cuckoo-lander 'offloading basic functionality to smart phones' bit. I don't know if there's actually anything to actually remark on about that particular choice, but I thought I'd just mention it before blathering about paying for online multiplayer.
The argument I've seen is that for PC gaming, is that since it's generally trivially easy to run your own server, you can't really charge a blanket cost to 'play online' with a given title. Someone else will pop up with something free, whether that's a server for your game or a game that fills basically the same niche, only free. That's the nature of the platform being much more open.
For console games, it's harder for servers to just pop up. I don't know if there are technical reasons, but legally I assume it's all proprietary, two of the options are literally corporate titans, and the last one is, as has been gone on at length about here, trigger-happy with the legal action. In the grand scheme of things $5/month isn't exactly an exorbitant price, either (even in a yearly lump-sum). With consoles being the cheaper, 'just works'-ier options to game on, it makes sense for people to foot that bill (especially if your Halos and your Smash Bros. are held ransom for it).
The only thing that really gets to me about the subscription services in general is that (at least, supposedly) most console games are Peer-to-Peer, which does beg the question of why the heck you want me to pay if you aren't at least going to put that towards dedicated servers.
All I have to say with regard to Nintendo's paid service is they are really wasting the grace period they gave themselves to prove they could at least meet par. I don't know that Splatoon 2, Arms, and the by-then 4 month old Mario Kart are going to make good enough hostages.