While it's true that most bats use echolocation via their advanced ears to hunt and navigate, having that ability isn't necessarily a tradeoff with good vision. In fact, a lot of them can see pretty well, with visual acuity varying across species. Under low-light conditions (for instance, during dusk and dawn), bats may be able to see better than humans, though color vision is a different story. Additionally, megabats (larger bats) can see thrice as well as we can.
