A ballerina lift-off sounds kind of nice, but it's really just silly, and potentially problematic. It refers to the "technique" of performing a calf raise during the lift-off process, where you "reach" for the bar.
When squatting, going up on your toes is one of the last things you want to do, at least if you want to keep an alignment that supports your body during the movement. Doing this, while at the same time getting the bar over the J-cups is, well, a problem. First, you have to balance. Second, it creates a reduced base of support.
Setting the barbell up at about sternum height/middle chest area is a safe bet for most people. Setting up correctly will lead to a quarter-squat type of lift-off, which also makes it easy to get tight during the set-up, rather than having to reach up to get the bar down.