That is pretty much the way microgreens growers
seed their flats, I can't think of any reason that it won't work in outdoor gardens.
As far as maximizing yield, that will depend on what you want to consider yield, for instance if it were beets, carrots, parsnip, horseradish or radishes just cropping the growing top might not kill the root vegetable right away so you would decrease yield because of crowding.
If it were an above ground crop other than the brassicas it might not have any loss of yield due to crowding.
It would indeed control weed growth because of lack of sunlight and that shade would help with moisture in the soil until the plants developed enough to suck the extra moisture from the soil.
The down side would be mold and fungal growth on the plant surface due to that same moisture.
I over plant then thin by pulling the excess plants, leaving around 6 inches between growing plants. We use the pulled plants as microgreens or baby greens. The only plants I don't do this way are
tomatoes, garlic and onions.
Redhawk