in contrast to helicopters we cannot land safely almost everywhere! Topology usually renders such diagram thinking unusable.
Perhaps. But, I would much rather arrive to my intended landing site, for better or worse, with enough reserve energy to accelerate upward from my descending glide path and arrest the rate of descent, before I slam into the earth.
When we see a "best glide" speed published for an airplane, "best" for what? The speed which will provide the least FPM rate of descent, or greatest distance until you reach earth is NOT the speed I would like to be doing when I decide to initiate a flare, or worse, maneuver around something as I cross the fence. Running out of energy there is the worst!
Remember, if the forced landing does not go well, you would rather that it not go well because you ran off the end of the area at 20 knots, ( I guess unless it's a cliff!) than because you undershot it at "best glide" speed and hit the hedge. Side slipping off the extra 10 knots as you flare is better than really wishing you had it!