The idea behind it is not that it just covers the ears, it is that there is a connection to equalize the pressure between the sealed off outer ear and the airway. I understand how it would help people with tympanic membrane perforations dive underwater without risking forcing water into the middle ear cleft, causing infection, damage, hearing loss, etc...
My personal take is that I would be concerned about failure of the system at depth, so I don't usually recommend it. However, every time it comes up, people who use them vouch for them so maybe they have a role. You just need to be clear on what you are risking. Unlike losing and replacing a mask at depth, losing this would result in a sudden flood of water into the middle ears with possible acute dive-related issues like vertigo, in addition to long term problems.