They're interrelated, all back to the original formula "power + attitude = performance".
The most common technique these days is to use attitude to control the aim point (therefore profile) and power to control the airspeed.
Airspeed with power? How do you recover from too low too slow?
I would be increasing the power and stopping/reducing the descent but making a slight pitch up attitude adjustment. What would you do? We're going to do the same thing no matter what theory we subscribe to.