Sharing answers to top q's we’re seeing about the thumbnail experiment: – Custom thumbs aren't going away – 99.7% still see the creator's custom thumbnail – A lot of creators use auto-generated thumbnails, this test helps improve them for those using them: https://goo.gl/A7oDmr
Problem is, you are looking at this as someone who makes their own thumbnails ONLY. The VAST MAJORITY of videos posted dont do those. Only regular content creators really do that. From a business standpoint YT smaller content providers will benefit from this... in theory.