Celebrities were swearing by them because all celebrities hire management/consultants to handle their money. There was a boom in NFTs among rich circles in California. They became both fashionable and a way to quickly scam some money together.

Since celebrity financial managers are all inbred with tech bro California money dorks, celebrities ended up endorsing whatever their management told them to endorse. Most celebrities probably didn't see it any different from doing a toothpaste commercial. They were told to buy NFTs to seem hip and to make money.

I don't think anyone has actually been driven into financial ruin from NFTs. The kind of people buying the things already had a ton of money to throw around for other useless commodities.

All crypto has been slowly dying since the whole FTX scandal.