It's still pretty fun to play as a secondary player under your own Switch profile. You get your own house to expand and decorate, you can buy clothes and change your outfit, interact with the island residents and visitors, catch all the critters (fish and bugs and stuff), collect and craft things and decorate the island. The main restrictions are that you can't pick the residents or move their houses around, you can't terraform (change how the cliffs and water look), and you aren't in charge of expanding the buildings that can be expanded (like the museum and the store). I'd say a secondary player still gets to enjoy like 85% of the game.