I generally figure that both realistic near-IR vision and realistic near-UV vision are perks, though arguably NIR should be slightly more -- its roughly:
- Can use an IR flashlight.
- Night Vision 1, when primary light source is incandescent or similar medium temperature thermal. Does not work underwater.
- Night vision 2, when primary light source is flames or similar low temperature thermal. Does not work underwater.
The night vision is because both light sources have emissions peaks in the IR, and are therefore brighter in IR than visible light. UV vision is a perk, it has no useful effects other than the ability to use UV flashlights (GURPS UV vision is completely dissociated with reality).