NFTs are safer than physical objects as they are stored on the Ethereum blockchain. As blockchain records every transaction, it’s more difficult to steal an NFT than to pull off a museum heist and steal a Monet.
However, just like physical objects degrade over time, so can digital art. The image quality may deteriorate, some file formats may become obsolete and can’t be opened, etc.
Still, it’s much safer and sturdier than physical art and is not easy to steal or destroy.