I never hold beginner swimmers in my arms, with their heads out and tell them to "kick".
If I were to do so, I would create poor form, from the get-go. I would create an arched back, a high head and feet up in the air.
Swimmers should not learn to swim by starting at the external, end result.
How can one learn about water while one's head, feet, legs, and more are not even in it?
In order to learn to swim, one needs to learn about balance, about the rhythm and movement of the water, how the water shifts and moves. The best place to learn this is by being still or by being moved in harmony with the water.
Allowing children to stand still in waist high water, is an exceptional teaching tool. Allowing children to learn to walk in waist high water is an exceptional teaching tool. Allowing children to hold their breath and hold their chin in the water and bodies completely still is an exceptional teaching tool.
Helping children learn to be perpendicular in water on noodles (in their armpits) or in a Stearns Puddle Jumper, or any floatation device, is an exceptional teaching tool. Even better is getting their knees and ankles to bend, in a marching, hiking, stomping or bicycle motion.
This teaches water treading, breaststroke kick, as well as the ability to later come up for air.
Quiet, smooth movements through water gain the best results.