truck tires (pro/con)

Considering that the TM is a tow vehicle...What are the REAL pro's and con's
of using high quality truck tires??? This of course assumes that one can identify
a "high quality" truck tire.... The reason i ask this is an business associate of mine
uses only truck tires on a construction type trailer ~25' hauling sand .rocks etc.
The trailers are single axel 15" wheels...He claims that 3k to 5k pounds are normal
loads and the tires are reliable and last for years!!!!!!
If this is true , Why are we so hung up on st tires????
I think WMTIRE needs to weigh in on this question
thanks for any input....
bill s