Well that's basically the reason why you are investing in an ICO, because of the product and if that product is ready and working then it's really a valuable project, a working product will take out all the uncertainty to investors and will see the future of the project.
You're right. If the project has a product. The price of such a project is high. And everyone makes a profit. Investors, developers, hunters. This is a very important element of any project.
But the project is not always good to pull the project, many have a good product but it can not always give you a big profit , I think in this market it is better to look when the coin will be listed and then buy