the 4 ohm rating

im a little confused as to why buyers choose 4 ohm products.

now here's what got me thinking about all of this 4 ohm stuff.

i took a pair of mids into my rebuilders shop the other day to get new surrounds installed & we started talikng audio & he told me that about 75% of the blown driver's he takes in for rebuilding are 4 ohms & the other 25% was split between 8 & 16 ohms.

correct me if im wrong but when you run a amp in 4 ohms as opposed to 8 ohms isnt the amp working much harder to produce the inflated wattage at the lower ohms? & isnt a amp thats getting worked hard a bad thing?

the same goes for 4 ohm speakers,the 4 ohm rating only makes the speakers to appear to be more efficient & also creates the need for thicker cabeling for the lower ohm's.

i hope the answers can remain civil as i didnt start this thread to be a smart ass but i am wondering what(if any)advantages there are to having 4 ohm gear over 8 ohm gear.

take me to school here & learn me somthing because all im seeing is drawback's to owning 4 ohm gear.

mike.