once you start racing on the track the car is gonna force you to heel&toe.
because when you're braking hard the weight "moves" to the front axle.
now - when you downshift without heel&toe you rear wheels will lock for a short moment which can cause the car to move out of the line.
here's a fast lap where I heel&toe.
It's not 100% perfect but there's no locking of the rear wheels in front of a corner so I'd say - mission accomplished.
you don't learn heel&toe for show but you learn it because you don't want to loose your car while hard braking and downshifting.