The video does say that the random FIFO is more efficient than the boarding group thing, but you have to pay extra to get priority boarding, so airlines are incentivized to make the boarding annoying enough to make you pay for it.
until you "board first" with a budget airline at an airport that makes you stand just outside the gate in a common (loses queue) and un-airconditioned space until they're ready to actually board. Then paying for boarding first is an absolute privilege, especially when the riffraff can run to the plane first anyway.