Who can say what people do with such NFT collections? Is it just a way to support the artist? I do not see the point. It's hard to call it an investment when it's not made by a famous person or a team with a great reputation, to say that in the future it will be more expensive.
I think the simplest explanation for why people invest in NFT is to compare it to investing in works of art.
You can invest a lot of money in paintings or sculptures by already very famous artists and it will not involve any risk. You can also invest in the works of unknown artists and hope that one day they will become famous and you will earn millions, but this is very risky. Investing in NFT is practically the same.