Consumers want to know that they can trust a brand before making a purchase. Showing brands that use the product (or have reviewed it) is an efficient way to ensure purchasers that the offer is trustworthy. 

If major brands use the product being offered, or well-known media outlets have reviewed it or mentioned it, showcasing that can build a lot of consumer trust. Using logos to reference business partners, clients, or media mentions offers strong reassurance to consumers.