Weight is a by product of proper design principles. By building speakers and cabinets to eliminate or lessen the impact of the many problems inherent with building speaker assemblies, weight is accumulated. But there becomes a limit in terms of material cost, and effectiveness. You can make speaker cabinets from concrete, which would be very heavy....but would be an utter disaster sonically - cabinet ringing and resonance.
Many people also apply this "if it is heavy, it must be good" to amplifiers as well. Be cautious here as well, as it can be an indicator that proper design principles and materials were used in the manufacturing process. Something interesting about HT amps, and their weight. Many hifi amps weigh as much for 2 channels as HT amps for 5,6 or more channels. What does this indicate?
This should not be the sole factor in your decision.
