No..... Not it's a horrible idea at times in real practice.
IF these flashing yellow lights are done during slow traffic times .. ok yeah it's a fine idea.
However, in my area these stpid flashing left turn yellow lights are allowed at all times of the day. Which is plain foolishness. Routine accidents happen because of these magic flashing yellow lights. Because morons make stupid decisions ROUTINELY...
As bad as the drivers in Northern Virginia are, I haven't seen any issues with them understanding what a flashing yellow arrow means. Because they're EVERYWHERE in Northern Virginia. Not many "left turn yield on green" intersections left, except in the cities (which maintain their own signals).
EDIT: I'm the sort of driver that will pull into the intersection as I'm waiting for a break in traffic to make my left turn. I've noticed that many Virginia drivers either don't do this or if they do, they'll BACK UP if the light changes before they have completed their left turn. Virginia drivers in general seem to be unaware of how to make a left turn without the help of a green arrow.