Yes, I do remember passenger tires on TTs, it was when an 18 ft Holiday Rambler was all the rage and my TV weighted more than my TT.
If LTs are the solution to your problems fine. You should certainly use them.
But I doubt that all of the Tire industry manufacturers would go to the trouble to develop a tire for a niche market, sell millions of them; if they they did not work.
The ST was designed for TT and use with other trailer types, it is what the TT manufacturers recommend as replacements.
The discussion of LT and ST is on a par with which is better for pulling a PUP, an F-150 or an F-350?