From my practical experience, they seem to make a difference in initial engagement which in turn makes a difference in algorithmic promotion which in turn makes

From my practical experience, they seem to make a difference in initial engagement which in turn makes a difference in algorithmic promotion which in turn makes a difference in overall “performance.” Tracking what you click on versus what you don’t, you might recognize that certain thumbnails make you more likely to take a pass. For clarity, my experience is at hobby scale and part of that hobby is learning about youtube. Trying to make the line go up is fun (until it isn’t) and a little attention to thumbnails seems to make the line go up.