Heel and toe doesn't have to detract from the braking force. The braking is straight down, the blip is just a little nudge to the right.
I agree with everyone else. Heel and toe is not just about blip either, you need to MATCH the revs, you wouldn't be able to do that with a button.
Try doing it all the time, by never touching the handbrake, then you'll figure out the best position for you when you're not wringing its neck. Essential 7 driving technique, perhaps you need to play with your pedal positions? My throttle is quite a bit further away from me than the brake, so when I'm pressing on the brake, there it is just to the right.