It's just one of the endless varieties of reduced-carb dieting. Not all low-carb diets are almost-zero carb diets.
My doctor told me to try low-carb, but warned me not to go too low (admitting he had no idea what was too low), so I started experimenting and logging the results.
I follow an exchange plan with 2 startches and 3 fruit (which is much lower in carb than most exchange plans, and yet is higher carb than the early phases of most low-carb diets).
I've tried all sorts of "timing" strategies for carbs - evenly throughout the day - all in the morning - all in the evening.... and there are definitely some differences. I can have a carb for a bedtime snack - if I'm tired enough to fall right to sleep, but if I eat carbs too early in the evening, it often triggers a "munchie craving" for carbs that I sometimes can't stop - it's like being on a runaway train.
For weight loss, I'm not sure it matters when you eat your carbs so long as you're counting calories (and sometimes have to be cognizant of carbs as well). However, timing strategies may help you stay on plan, especially if they help you manage portions and hunger.
Evening carbs have always been a problem for me, so setting a "no carbs after dinner" rule has helped me a lot (but sometimes I "cheat" and eat my fruit in the evening - and sometimes it does set off cravings that I then have to fight all evening).
The only way to find out if a carb-timing strategy might work for you, is to try it. As to why it works (when it does), it's a bit of a mystery. There are a lot of theories, but they've not been rigorously tested.