Let's say you give $50 to a kickstarter project, and in return you get some special benefit, say early access. If this was tokenized, as you follow the project, you could sell early access. If you thought it was less likely to happen, maybe you sell it for $40. If it was super exciting, and the founders capped how much early access there could ever be, maybe you sell at $60. This is the benefit that tokenization gives you. You don't get any say in the company, any stock, etc. - you get access to a product, and through the blockchain you can easily trade it securely and provably.
People who buy diamonds, physical diamonds, may be speculating on them. Others may actually like the diamond. For whatever reason, they bought the diamond, and now own it, and can resell it. It isn't illegal to buy something in the hope it goes up in value. People do that all the time with videogames, cars, whatever.
Now, let's say ownership of a diamond was moved to the the blockchain. Not only could you buy and transfer it easily, provably, securely - you could even buy 0.000000001 diamonds, or 100000 diamonds, just as easily.
In my opinion, all of this is objectively better than kickstarter.