An alternative version would be to spend the first months trying to sell the product to customers even before it exists. Try to validate as soon as possible, then build and deliver the product.
1: I don't think it's a thing done in Silicon Valley at all. It didn't even originate from Silicon Valley. OP is based in Europe.
2: Free information is always of value, so how is this making it less valuable to the user? If it works as marketing for the host, so what? Doesn't make it less valuable. I know more now about company X than I would if it wasn't open. It's that simple.
3: Many countries around the world have a very open system where you can go to a government or private website (the information is usually provided by the government) and look up financial information about every company in that country. For example, here is Volvo in Sweden: https://www.allabolag.se/5560125790/aktiebolaget-volvo
An alternative version would be to spend the first months trying to sell the product to customers even before it exists. Try to validate as soon as possible, then build and deliver the product.