They might've also been thought to be helpful for formation flight during refueling the aircraft they were originally installed on, the KC-135, from another tanker??

They were definitely not useless, they are wonderful during a circle-to-land, when the circle is constrained by terrain to a turn-to-final in the direction opposite the seat the flying pilot is occupying. That glimpse thru the eyebrow windows is worth a thousand words. But if you don't have an opportunity to put them to use, you might have an opinion that they're useless.