Its 2 more hrs of photosynthesis every day so theres that! I like the 20/4 schedule personally. Where i live i dont pay for electricity so im cool with it. Especially because i run a lower wattage light in one of my tents, it lets me hit the DLI with those two extra hrs so yeah, I can see that.
i dont think its beneficial in 100% of situations, but can def be beneficial if it lets you get enough light to the plants. I run on the lower wattage side, if i was blasting em with higher wattages i would dial the lights back a bit. So if it makes sense, run with it!