Reggie has pretty much hinted that a cloud service is in the works. Someone had sent their Switch for repairs after losing their data, but when it came back, all of the data was "magically" restored.
...And for goodness' sake, I doubt little children will want to pay an extra $20 to use online. The main bulk of the series is staying on handhelds. If something real important comes out for the Switch, it'll surely be another Pokemon Colosseum-kind of thing.