The point is we have adaptations that allow us to handle the amount of light we live in. As humans, it’s not sensitive enough for moonless night activities and not adaptive enough to handle staring at the sun, but appropriate for most earthly activities. Meanwhile, nocturnal eyes in other animals are easily overwhelmed in daytime and diurnal eyes can be even less useful at night. So for this alien, we can’t decide if it’ll be blinded or perfectly competent at handling our local illumination. All depends on if it evolved to hide between stars or eat inner planets