I need to buy a product that I've never bought before.
I don't have a clue how much it costs. I search Google and your website appears near the top of the list. I click on it.
Will your site give me an answer to my question about price? If I'd buying a specific widget I'm sure that it will, because a shopping cart without prices won't sell anything.
But what if I'm sourcing a bespoke product? Say a patio door, some business consultancy, or a new website design. Will your website give me some indication of the potential cost?
Because if it doesn't, I'll probably move on to check a competitor's website. And I'm unlikely to come back to yours. Ever.