I mean this is generally a sign of growth by the content creator, shifting from whatever "personalized" ads the ad network decides to show, to having their own relationships with advertisers and doing their own ads. Honestly its a good thing because it means that the people making the content also have full control over who they sell ad space to and how that ad space is used, and if viable platforms other than Youtube existed, they would be able to to run their videos profitably without excessive user tracking