Power + Atiitude = Performance. You are actully manipulating both the attitude and power to achieve a desired outcome. For teaching it is best to tell the student that on base they are controlling the rate of descent with power and airspeed with elevator, so that they arrive turning finals at 600'. On finals the aim point is kept constant and speed controlled with power.
If you try to teach a student (ab initio) on base that power is controlling the speed and elevator the flight path, there will be a few senarious that they wont understand, firstly high and slow, they will apply power. Another classic is fast and low, they will decrease power, and end up even lower.