I concur totally with the last post, and site the first posts as simply incorrect. Large powerful amplifiers are necessary to provide instantaneous current, dynamic headroom, driver control and impedance matching.
It is not simply a matter of watching the RMS power meter. If that were the case, most people would never need more than 30 or 40 watts, MAX.
I have listened to multiple systems, at calibrated volume levels, and switching the same manufacturers smaller and bigger amps in and out. The differences are real and audible.
Flubby bass notes became clear and displayed new timbre. Leading edges of sound were more real, tones truer. Suprisingly, the smallest details sounded clearer, more life like. In neither case was one amp capable of more volume than the other, but the larger amp was always better at all sound pressure levels.