Matching revs is really the point of this one. Why is that important? Well, when you use a manual gearbox you are asking the synchromesh to assist you to bring the engine speed up or down to match what is needed for the gear selected. If you didn't have synchro you wouldn't be able to select the gear, or if you managed to do it you'd get an almighty crunch. This is very inept and uncool and was called 'a crash box' technique.

Let me explain. When you go down from 3rd to second you need to 'blip' the throttle and raise the revs as the gear ratio will otherwise force the engine to increase revs to match the roadspeed. It's very uncool to just let the synchros do it, and can cause driven wheel lockup when done too suddenly especially on poor, loose surfaces. This often happens when decelerating, and often again when you need to brake as well. It's dangerous and unnecessary.

Instead let's blip that throttle and raise the revs as we downshift; in fact let's keep one foot on the brake but use the heel or side of the foot to raise the revs (ie blip) instead of lifting off the brake. It takes practice, but it's smoother, faster and better as you can therefore brake and change gear simultaneously. Racers use it, you should too.

Frankly, if you don't heel and toe then you are a danger on the road and should consider swapping to an automatic transmission. You certainly won't post good lap times on the track if you can't get the basics happening! (Yeah, I'm opinionated but it's true. Want to do even better gearchanges, look up double-declutch.)