Consider that a user from a search engine comes to your site after searching for “buy coffee makers” or “best coffee makers.” These are “buy” keywords, and they are looking to buy a coffee maker, so offers for those will be considered much more seriously, meaning they are more likely to convert.
On the other hand, another user comes to your site because you created a viral video demonstrating how to make an iced vanilla ice cream latte. That user is not likely to be interested in buying a coffee maker since they likely already have one. That is why they want the recipe, or they are just curious. Because they come to see the viral content, the bounce rate of viral website traffic tends to be higher and conversions much lower.