Yes it would be a waste of money to make things convenient for the players and to make sure that the console is as feature-complete as possible on the day it is launched to the wider public. When the people actually start to interact with it and its online components.
I'm not insinuating that software development is free or instantaneous. My point was more that Nintendo has the money to afford software development and should've had enough foresight to have the front-end for the online functionality of their new flagship console developed when that console hit mass market. Not a couple weeks later, not a couple months later, but when it comes out. That they said they'd add it later doesn't really help their case any given how it just outright states that the console is not feature-complete on launch. Which is not a good look for a hardware manufacturer.
Of course given that Nintendo had a pre-set date for when the console was released (or at least the general month of it, since they are just desperate to catch the end of the financial year) they should've taken measures to make sure the online functionality of the system were as developed as it would be, with all the things they planned for it to have being in place. To put it simply: they should've started work on it earlier.
Once again, Nintendo is a multi-million dollar international corporation. If they screwed up when the development for their online components started, it's entirely on them and just makes them look incompetent. They have had 10 years (2007 was when the friend codes first appeared IIRC and people decried it as a bad idea back then already) to adapt and change how they approach online functionality design. They have the money to hire outside experience if they haven't learned anything. But seemingly they did neither of these things and just went to the old reliable fallback of half-arsing it.