Amplifier current vrs watts; why is current more important?

As an analogy using cars, watt is like a car speed, whereas slew rate is car acceleration.  

Let's say you have two car: a good old American muscle car and a Ferrari.  Both cars may be able to do 150mph, but the Ferrari will accelerate to 150mph much faster than the muscle car which is what most people want.

Andy, are you addressing the Q of the OP or changing the topic? You say that both wattage and current are both static variables. How have you advanced his understanding about his Q?

Andy, are you addressing the Q of the OP or changing the topic?

I think the OP wants to know why current is more important than "watt", but I think what he really wants to ask is why two amplifiers may have the same "wattage" rating but one amp may appear to have more "power" than the other.  He is thinking maybe because one amp has more current therefore more power.  It is only partly true.

My response was meant to say the "current" itself may actually not it, but a better characterization of how "dynamic" the amp is by using slew rate measurement.  

So in that sense, I was responding to his "inquiry" but may be in a different way.