I should say that I am able to hockey stop both directions relatively consistently using the method in this video .
I have a harder time pivoting while continuing to move more or less straight down the hill.
I take issue with the video piece's use of the phrase "foot rotation" to describe what is used to make a hockey stop. That terminology can be misleading, because the rotation should be of the full legs, starting at the hip joint. I think of "foot rotation" as being rotation of the feet relative to the knees. This movement is made entirely below the knees, and results in flattening of the skis, not at all what one needs to create the edge angles for braking in a hockey stop. It's very important for developing skiers to reach an understanding of the difference between these two movements.
However, the demos in the video are fine.
This is a good exercise to practice. The goal should be to develop the ability to make the hockey stop in a straight line down the hill. This requires management of the relationship of the center of mass to the skis, management of flexion of the joints, and refraining from tipping the feet into the hill strongly until the skis have pivoted perpendicular to the fall line. A common fault you will see is a skier scooting out into a fish hook before stopping. This is a result of too much edging, and too much pressure on the edges, too early, before the skis have fully pivoted.
In the last part of the video, the demonstrator shows how hockey stops can be modified to use as a method of ending one turn, and making the transition into the next turn. Some of us like to call these "hockey gos." These can be quite useful in steeps and tight spots, but I would NOT recommend making them a basis for your go-to turn pattern. Most of the time, we look to avoid jamming on the edges, which is fundamentally a braking maneuver.