Keeps more of the sugar producing leaving in direct sunlight, which believe it or not is important.
This is the part that makes the affirmative argument, for me.
How can the stuff that isn't getting direct light, still produce something worth the energy consumed? If those leaves are in shade (from the top of the plant), they aren't "pulling their weight," and so energy they
should be harnessing for their own local fruit, has to be diverted from the energy harnessed by the upper leaves, which are in direct light... but in diverting that energy harnessed by those upper leaves, what impact does said energy diversion (or dilution) have on the top-local bud/fruit sites?
I would expect that if the top leaves are having to carry the whole load of light energy conversion, then they most likely won't be producing their best fruits at the top OR the bottom... because photosynthetic efficiency has limits, perhaps? How many buds can one whole leaf efficiently make?
However, increasing light penetration depth, would then move into the realm of having more leaves harnessing energy, per light source, in which case it might be much better to minimize pruning (or, it's always better to "minimize" pruning, in that you want to do it as little as possible, just on the "minimized" side of exactly the right amount). Pruning too much is obviously increasingly detrimental, after a point... but knocking off a couple shaded bottom leaves probably has an irrelevant amount of impact.
So, probably best to try to keep as much of the plant as you can, bearing in mind a few fundamentals, such as "leaves need direct light to photosynthesize at maximum efficiency, so shaded leaves will consume energy to grow, but won't give much back in the form of harnessed light energy..." so probably better to remove anything that isn't getting ANY direct light, and perhaps even stuff that gets less than 50% direct light.
You wouldn't want to spend a bunch of money on solar panels to harness sunlight, and then place them in the shade... so why would you want to spend a bunch of the plant's energy to grow leaves that won't touch enough light to be worth growing? Nip them as soon as you know they won't get enough light to be worth the energy required to grow them. Waiting longer is wasting energy (e.g. resources, nutrients, electricity, time...). If you wait too long and they become retarded branches (slowed and with little chance to fully develop), maybe try to manipulate the canopy so they get light... or just chop 'em.
All i can cite is the wealth of information available on this topic (this site and others), and limited personal experience.
I can see both sides here, but through my own experiences, have discovered which side of that line i reside. Sure, it's cool to "just let the plant do its thing, man!" but sometimes living things don't do their best (or what you want) unless you manipulate or modify them in some way.
This is what one gallon pots look like in my garden. I can fit 36 under one light in a 5x5 tent. Produce 20 to 35 grams per plant. That's about 3 pounds per light. In soil. Organically. Welcome to the big leagues.
