Introducing traffic through Google searches rather than including a link is much more valuable

I mean sure. But then you're counting on them to actually perform those searches.

users tend to check (and buy) more in detail if they find the product by themselves

Yeah no shit. Because the act of searching indicates they're already interested in purchasing the product. You're working the logic backwards. It does nothing if they just can't be bothered to search for it and never find it. You're just adding friction for no reason.