I have a little different take, unless needing the extra alternator to run a large motor load like a winch or hydraulic pump or extended time on engine off accessories not going to see huge gains. As far as charging the camper batteries the charging circuit in the trailer plug is going to be the limiting factor. The extra 157 amps availability isn’t going to charge the trailer batteries any faster running down the road using factory installed trailer wiring since circuit is limited to 30A. To take advantage of extra amperage would need to add additional wiring to the trailer/camper. Modern LED lights really don’t draw much so unless trying to rival the sun with light and match truck price on lights or DB drag stereo system standard alt will support additional lights and small stereo upgrades no issues with engine running.
The option is very good choice if running a plow, heavy winch use, dump bodies, small body crane, Tommy lift, extended light use with engine off and such. Personally don’t like paying for things I don’t need especially since having to maintain 5 batteries in the boat and 2 in the cargo don’t want any extra batteries to maintain when not in use for the truck. I should buy stock in battery tender
. If sitting for long times in cold climates without a maintainer there is a advantage of additional reserve capacity to allow for longer unused time before there is not enough reserves left to start the truck.
To each their own and if it is what you want go for it. If planning on a heavy electric motor load or future proofing then definitely get it. Wthout large electric motor load or long sit times without battery tending (weeks+) standard alt and battery will work just fine. Ultimately it is your choice and what works best for me may not be the best for you but can make a informed decision.