There is a big demand in NFT and many developers of the games use NFT to attract their attention to games.
The opportunity to earn money attracts a lot of gamers to NFT and allows people to earn money by playing.
NFT allows earning money for many people. Many people create NFT to earn money. Other people earn money on collecting, buying and selling NFT.
A lot of people buy NFT and use them for investment purposes. It is possible to make even more money on NFT than on altcoins.
That is why there is so big demand in NFT.