I would say yes that’s more or less correct.
Stationary lights bake down two things: Shadows and bounce lighting. Direct lighting is still dynamic. So you can change the intensity of a stationary light at runtime, but this doesn’t affect the bounce lighting so the skylight continues to glow as if it were daylight, even at night. By using a zero-bounce skylight, there’s no bounce lighting to bake down so you’re only using it for shadows.
Example:
The obvious question is well, why not just use a moveable skylight then? Well… because moveable skylights are unshadowed and DFAO is not a suitable replacement for skylight shadowing.
Essentially, if your project has a Day/Night cycle, you have three options when it comes to the skylight:
Moveable Skylight
Unshadowed
Provides proper darkness at night
Stationary Skylight with bounces
Properly shadows interiors
Bounce lighting causes exteriors to brightly glow at night
Zero Bounce Stationary Skylight
Properly shadows interiors
Provides proper darkness at night
Zero bounce skylight offers the best compromise by far…