Streamers and other popular YT channels rely on ad revenue from their YT channels. If they play content-id-ed music, the revenue from those videos might go to t

Streamers and other popular YT channels rely on ad revenue from their YT channels. If they play content-id-ed music, the revenue from those videos might go to the music rightsholders instead. For channels which aren't going to be able to get ad revenue due to their content not being "advertiser-friendly" this is not a concern, since they make their money elsewhere.