For the players?
If you have ever logged into your Epic Games account on Playstation 4 you will not be able to use the same account on the Nintendo Switch, or any other console version of the game. You can access your progression on PC if you play on PS4, however you will not be able to access that progress on any other console. You cannot un-link your PS4 as a primary console and link the Nintendo Switch instead. It appears that every other platform will allow you to carry progression across, meaning your purchases and progress is not erased and you aren’t forced to start again.
This is an incredibly anti-consumer move from Sony, who’ve already come under fire for refusing to engage in console cross platform play. Fortnite is currently cross play across Xbox One, PC and Switch, but Sony exclude the PS4 from this. You can play with PC players on PS4. This is a huge let down for Fortnite fans, PS4 was the most popular platform for the franchise so a lot of people hoping to play on Switch are currently devastated due to Sony’s anti-consumerism. We are currently awaiting a statement from developers Epic Games, this article will be updated as the story develops.