You are right. There is absolutely nothing like it, i.e. nothing quite as ridiculous as trying to increase your cycling performance by pretending you are pulling up on the pedals. Some people can rub their stomach and pat their head at the same time, but not me. As for efficiently pulling up with one foot and pushing down with the other, then switchiing at just the right moment, well good luck. In my experience it is imaginary. Oh, being clipped in or on is great, no other way to ride, but not because of the mythical pulling up.