I have to admit that at night, on a circle, I would like to have glidepath assistance. You are close in and needing to transition from level to an accurate descent path probably slightly before you are wings level on C.L. PAPI's would help this enormously. The error margin is very small. A visual circuit at >1500' should be possible for a competent pilot, but is so rarely practiced that it seems safer and more sound commercially for an operator to insist on PAPI's.
Daytime, that's another issue. There has been comment about 'not being trained' for this or that. There are some operators who have that philosophy, which limits them sometimes because you can't train of every eventuality. Which brings the debate full circle about the depth of basic training. I know the opening thread was not about that. Sorry.