We all know that it was not really "art", it was banana taped to the wall, and even the owner said that banana could be changed it was the "idea" that was the art and not THAT banana that makes it art. Do you really believe that a banana taped to wall worths a ton of money? We all know it shouldn't however it became viral and probably worths even more right now, art is a bit weird like that.
I do not consider this NFTs to be like that banana taped on the wall. The reason is that there is more effort and cost in making and selling of these NFTs compared to that eaten banana. However, these 2 kind of arts has value for some people, so they are willing to pay for it. It's been what things are recently, I think we shouldn't be that shocked if an NFT is sold for hundreds of thousands of dollars. The "idea", "symbolism", back story, subject, uniqueness, etc. are reasons why these kind of arts are valuable.