However, one major multiplayer game will work without a subscription: Fortnite is playable online even if you don't have an active online subscription.
The most basic perk of Nintendo Switch Online is online multiplayer gaming - if you want to visit a friend's island in Animal Crossing: New Horizons or battle your buddies in Super Smash Bros. The Expansion Pack tier doesn't add any restrictions for subscribers on family plans, so it'll work the same way as it does on the basic tier. It's possible for the administrator to set other accounts in the plan as 'supervised,' letting them restrict eShop purchases and viewing, as well as reviewing sign-in history.