Purpose of power handling in the specs?

So I’ve never quite understood this:  What is the point of manufacturers listing power handling in the specs?

I ask this because I’m now listening to a 89dB efficient speaker, rated to handle between 50-200 watts of power, with a 7 watt 300b integrated.  Logic would tell me that even with the volume maxed out I should get almost no volume from the speakers.

Can someone please enlighten me as to the purpose of the power handling specs?

Thanks.