Definitely! Movie posters and book covers (regardless of the old saying "don't judge a book by it's cover") are often the things that draw me in! So having the ability to do that on videos with the custom branding would be great!
I am definitely excited for this to be rolled out to everyone. I don't know why but custom thumbnails just seem like a very good thing.I heard you are only able to get this option if you have over 5000 video views total, I recently switched to a new account and have around 2600 views and i don't have the custom option, where as my old channel had well over that many views and the option was there. I don't think it's subs that matter to get this option, just views, and a good standing channel under the account status section on your channel overview page.