Out of stock
To stop save scumming among other examples
Nintendo have decided not to enable it on "some games" as an anti-cheating measure. E.g. In games that offer a random bonus, you could reload and play until you got the best bonus. It is not clear exactly which games they will apply this too, but at this point they have specifically called out Splatoon 2. https://uk.ign.com/articles/2018/09/10/some-switch-games-seemingly-wont-support-cloud-saves The same statement seems to have been sent to multiple games news sites.
Because Nintendo what?