A tree can easily provide deep shade, regularly in the middle of the photoperiod, as the sun moves in the sky. So can other obstacles, both natural and unnatural.
Don't take nature too literally. The sun doesn't go on and off instantaneously with the flick of a switch each day, yet our aquatic plants in glass cages subjected to this and many other unnatural occurrences grow fine anyway.
I've tried breaks and found neither improvement nor harm. Some say it helps with algae problems. Others use it to better fit a limited photoperiod around their personal schedules, to increase viewing time.
My reply was literal. Remember I said observe nature and learn. Implying everything you wrote in the first papragraph. However his question is: Which is better
? Not, Will this be necessary
? As to your second paragraph, frankly none of us know what affects short intermittent photo periods have.