This has been revealed by Nintendo's official AU website where it is written in the product description. Check out the official statement from the store listing below. Please note: Nintendo Entertainment System Controllers can only be used while detached from the Nintendo Switch system, and only to play NES – Nintendo Switch Online games. Nintendo Entertainment System Controllers can be charged by attaching to the Nintendo Switch system. The website also states that the controllers cannot be used while attached to the system and you will need to detach them from the system to play games with them. They can only be charged while connected to the system. These restrictions are increasing day by day as they get revealed by Nintendo and thus making the purchase of these nostalgic controllers very difficult for Nintendo Switch owners.