The reason an RV park 50 amp outlet may be better for a 30 amp rig using an adapter is because those park outlets get a lot of use and abuse. Well worn outlets are going to have more resistance the worse they get. The 50 amp outlet is heavier duty and will likely have less resistance than an equally worn 30 amp.
For your home service there is no real benefit to installing a 50 amp except for possibly getting a 50 amp rig later. Your current 30 amp rig has an internal 30 amp breaker limiting you to 30 amps no matter what you plug into.
