The difference with regular music uploads and Deadliest Metal is that DM always releases content with clear supporting information for the artist such as album purchase links, merch links, label links and other relevant info. This is what gives DM an aware and active supporting role for the music it uploads.
The Bandcamp section of DM publishes a select few of the artists songs and refers the listener to the bands own Bandcamp page to be able to listen to the rest of the album in order to create traffic to their page. This is done with the cooperation of the artists.
Deadliest Metal puts effort into the presentation and quality of the promotional content it releases on YouTube because good music deserves a good appearance that does the music justice.
The visuals are made with a custom professional looking format to better present the album artwork and the quality is always 720p minimum in order to have a reasonable standard quality.