Without question that is a consideration… part of the ST tire design is that it complements the ride and is a part of the vehicles suspension system the more rounded sidewalls are a part of that design…
Generally speaking the straight sidewalls and the higher load rating and air pressure that would be needed in the LT to equal the ST’s load rating would provide a significantly harsher ride… and I am sure plenty that will argue otherwise…
I might add I have used Maxxis UE 168 tires, but not on a trailer and I wouldn’t use them on my TT and they were only marginal and very fast wearing on a van…