NFTs are stored either on your wallet or in a market-place where you have bought it, for example on Open Sea. Personally I don’t invest in NFTs as I don’t see real value in digital pieces of art. Nevertheless, I invest in multifunctional NFT-projects.
NFTs can be a good thing for new projects to attract investors. Because of hype many investors are willing to invest and get NFTs for this as they hope that they will sell them for a better price.