Alot of PPLs tend to get their NVFR so they can come back a bit later and not get caught out by last light issues.
I also think basic CPL holders get a NVFR so they can do freight only jobs in 210s and the like and get some experience and money in before they spend it all again in gaining a ME-CIR.
I did it as it was a requirement to do an instructor rating and I was also able to get the elusive night hours initially by teaching NVFR myself.