Hungaluz: Yes. Done correctly, 2D-training in a "compressed" (<10cm from plant) grow area is very efficient in terms of g/m2 and g/w.
Light, electricity, CO2, and space are all assets/inputs (actual or potential) which can be maximized. Focused light grows plants, while un-focused light is either harmful to soil biota, or heats up everything around it (requiring subsequent cooling). CO2 can be a fantastic growth stim, IF it's where the plants can use it, not puddling on the floor. A well-made LightCanyon would do this.
Training is always a trade-off between plant-stress and effect (time, money and hassle may also be factors). I think this espalier/vscrog multiplies the number of effective bud sites (a la scrog) w/less stress on the plant. It is also easy to adjust as the plant grows/changes.
Plant energy goes into roots and buds only. The main stem on the plant is thinner than a pencil, secondary branches are only slightly thicker than the twine they encircle. She has been well, but not overly, foliated her entire life cycle. No de-fol and no need of it. This would only improve if the set-up were free-standing and lit from both sides, rather than relying on reflection while shackled to a wall.
Set-up time and routine maintenance are quick and easy. This could readily be scaled up to a commercial technique as you have seen in local vineyards and orchards. Break-down consists of snip-snip-snip.
I like to garden, due in part to the fact that I like to BE in gardens. For me, this is not LasVegas during a howling gale. Fans are noisy and expensive since none of the ones I could find run on Love. Since sturdy stems aren't relevant, fans can be kept to only that needed for enough air movement to deter mildew/fungus. If the garden is unpleasant, you're less likely to be there and as Confucius so wisely said: The best fertilizer is the gardener's shadow.
Clearly I'm proud of my grow, and I hope this Pride did not skew my analysis too wildly. Questions, comments appreciated.
Love and respect