I judge books by their covers almost every single day.
I happen to mean this literally: every morning, I get an email from Amazon with special offers on Kindle books. And unless I spot a book that a trusted source had previously been recommended to me, I choose which book images I'm going to click on to learn more about (and consider buying) based entirely on their titles and how their covers look.
Why? Because I simply don't have the time to click on every single book cover featured in that email, read every description offered, and carefully consider which of the books I might purchase... especially since all the books are offered at $4.99 or less.
Am I missing out on some really great books that have names I find awkward or covers I think are initially unappealing? Almost certainly.