I'm a big fan of replacing trailer tires with LT tires when you can find a matching size and weight. They just don't have the issues. Our friends bought a new Cameo fifth wheel and blew two of the four tires in the first 12 months. Cameo replaced them and those blew. He finally put the LT tires on and now....6 years of service and no issues.
I don't think sideways movement has any impact on LT versus trailer tires. When I bought my new 4500 pound SeaRay boat and trailer in 1990, I immediately replaced the trailer tires with steel belted radial, passenger car tires. The trailer handle better, drove smoother and didn't bounce like it did with the trailer tires.