Regardless of whether the pedestal is 50 or 30 amp, you ONLY have 30 amps max for use in your trailer via the power cord.
If you install a 50 amp pedestal, you could use a 50 amp male to two 30 amp female splitter. Plug your trailer cord into one 30 amp female end and a 30-20 amp dogbone into the other and use that to plug in an electric heater, etc., separate from the trailer system.
Outside of that, the only benefit of adding a 50 amp instead of a 30 amp is if you decide to get a new RV at some point that has 50 amp.
Doing a combo pedestal like Bobbo indicates would provide for all three of those scenarios.
