not trying to argue the point but there is no "overall". Observational data is not scientific and is considered anecdotal and not really relevant. Trying to determine the acuity of any animals vision or reliance by observation would call for the operation of that animals brain. Owls can fly around the speedway with absolutely no light and it would be primarily from their vision so the lack of light is irrelevant in how the rods/cones and physiology of the eye integrates into the animals brain. I understand that there are many variations of vision in bats but there is no science to support the "overall" statement. In some cases that may be true and in some cases it may not.Visual acuity varies from species to species. Some are able to detect colors and light intensity, some can see in the UV spectrum and they use vision while mating. But in overall eye function their eyesight is significantly less than a human's.
As for being "in all intents and purposes blind" referring to the bats I was watching at night. Do your own test. Le Mans speedway. You are in a Formula 1 up around 100 mph snaking through the turns and curves, the track is unlit and the car has no lights.
Nifty web site about bats: https://www.doi.gov/blog/13-facts-about-bats
Every "scientific" publication that says they are blind or lack good visual acuity can be matched by one that says they aren't. I was simply trying to point out that Bats are not blind at all and may CAN see as well or better than humans. There are probably many that can't as well just like with birds. It's those coin phrases that further misinformation that I get concerned about because the goal should always be to educate and education should always defer to science first and anecdotal experiences last.
I'm a big fan of bats and they are an animal with a great deal of misinformation around them especially the issues surrounding their sight.