Braid is very limp which makes it easiest of the lines (mono, FC, braid) to get smoothly through guides, in general.
But proper guide design/layout is important with it, as with the other lines. Latest thinking on design for spin rods (and to a lesser degree, cast) is to use higher guides than we used to, and smaller guides to try to get the line under control fast, in only 2 or three guides, then use all the same size running guides to the end. Many have theories on why micros work so well (with all lines after the reduction is accomplished), but my theory is that they control the line looping so that the line is essentially a very long and small cylinder going through the air instead of a looping line trying to cut the air resistance. In any event, most agree that micros cast farther than bigger guides. Even if this is not true, they cast just fine and because they are small they add little weight to the blank. Weight is an enemy of sensitivity and fast response/recovery. But keep in mind that proper design and layout will get the line under control before it gets to the micros.
As usual with new technology, rod builders went crazy over micros and applied them where they probably were not the best guide. Many builders have since settled on size 4 spin guides (4mm O.D. of the ceramic ring) and size 5 cast guides since these sizes are very light AND they pass leader knots better. Some used micros on fairly powerful rods and the tiny guide feet sometimes failed in the midsection of the rod. Fuji has micros with bigger feet to handle this issue.
http://anglersresource.net/ Go to this site and watch the 7th video down on the Fuji KR Concept guide system and you'll get a more professional treatment of what I tried to describe.
Regarding the video, I'm sure the one who made it thought it was correct, maybe it was done a long time ago, but you will probably not find a builder today who would agree with it. Regarding the weight of braid, most braids are lighter (density) than mono or FC as manufactured. I expect it is heavier when wet, but I have no data. FC is the heaviest with a density of about 1.5 times that of water. Mono is about the same as water. Some braids have heavier fibers woven in to make them sink, and because of the heavier density and their very small diameters for a given pound test, they are very good for getting deep when you want to.
But it's the reduction train that has to be considered too. See details above.