If I was hauling cars for a living, the less wieght the better. Also can make hooking tie downs up easier.
Anything else, they suck.
True, I Google image searched to make sure I wasn't remembering wrong. So many different types of trailers and campers.
If you have a camper with the drop down booty, a low deck may help keep it lower. A regular ~8' camper like the 2 I have had, I'm not sure would clear a standard goose tongue on a low deck.
There's also different hieght tongues
newer trailers seem to have higher tongues. My old work opted for a +6" for more bed clearance than our older trailer. Thing showed up with like 18" between the tongue and tail gate of a stock F350