One issue is that a lot of these publisher-specific channels have pretty shitty practices. For example, Bethesda decided to not allow refunds of Fallout 76; had it been on Steam, disappointed players could've used Steam's refund policy to easily refund the game as long as they didn't play more than two hours of it.
The relationship between the publisher and the player is often antagonistic, as shown by Bethesda's refund policy, the rootkits Sony installed on their customers' computers some time back, DRM which requires the player to always be online, etc. A somewhat trustworthy distributor distributor will help make sure that the game _probably_ won't actively harm your computer, and that you can get your money back if the game otherwise doesn't work for you.
The relationship between the publisher and the player is often antagonistic, as shown by Bethesda's refund policy, the rootkits Sony installed on their customers' computers some time back, DRM which requires the player to always be online, etc. A somewhat trustworthy distributor distributor will help make sure that the game _probably_ won't actively harm your computer, and that you can get your money back if the game otherwise doesn't work for you.