https://www.polygon.com/nintendo-switch/2018/9/8/17834982/nintendo-switch-online-cloud-save-support

Several Nintendo Switch games — including some big names — will not support cloud save backups when the Nintendo Switch Online service launches, the company confirmed to Game Informer yesterday. The reason why probably won’t make anyone feel better either.

In a statement to Game Informer, Nintendo said that with backup saves stored in the cloud, users would be able to revert to a higher online multiplayer ranking, or get back items that they’d already traded to another player.