yar agree...no point figuring out how they work..as long as they are doing their job and we get what we want.
I use Uv for all the tanks i setup..sort like add more equipments to mark up the price.
but uv do help in producing crystal clear water, i even install uv for my fresh water setups...but overdoing it would create more trouble then it really has in the begining. thats why a timer is important...just let it run a few hours a day.
if ozone is used, i would skip uv all together.