As Epic Games continues to work towards an echo system that is better for games, PlayStation players now have access to a shared wallet in Fortnite.
The Shared Walter system simply means that any purchased V-Bucks on your profile on PlayStation will now be accessible on the other platforms already partaking in the Shared Wallet eco-system, which is now everything but the Nintendo Switch. Any V-Bucks you earn from battle passes or other in-game events or modes will be useable on any platform, including the Nintendo Switch.
You can play Fortnite on PlayStation, Xbox, Nintendo Switch, Android and cloud gaming services (currently the only way to play on iPhone), making Nintendo is the only developer yet to play ball when it comes to the Shared Wallet.
Any questions about Shared Wallet can be answered on the Epic Games FAQ page.