I hold a MECIR , NVFR , and night AG ratings and funnily enough the only one I would feel comfortable using right now is the Night Ag .
The key word for me is "comfortable" to which I'd add currency.
I'm comfortable with night Ag in an aircraft on which I'm current and familiar but I haven't flown Night VFR since the rating test in the early nineties and my CIR is 2 years expired so wouldn't even consider entering IMC for one second and would probably sh!t myself if I did.
The line of using a NVMC rating to get home after last light simply doesn't work as you won't be legally current or competant unless you fly at night regularly.
As others have said it's the loss of emotional control that goes with unplanned night/IMC flight that often preceeds loss of aircraft control.