Because I almost always dry camp and I have a total of 4 RV batteries. I most certainly recommend it.
It also has another benefit. Because the batteries are on a completely different circuit. In the case of your engine circuit alternator failure. You can use the RV battery circuit batteries to jump start the engine. I do have a overhead camper so this becomes more apparent. Two RV batteries are under the hood connected to one RV battery in the camper and one in the trailer. I use the slide in type connectors from the ends of two jumper cables to connect the trailer to the Camper. Forgot the size of the wire, but they are thick, connecting the two under the hood with the other RV batteries. I have a 100 amp fuse on that lead at the batteries.
I did use this once. While out in the middle of nowhere. Just make sure you have a set of jumper cables as part of your tool kit.
If you have a overhead camper. I certainly would recommend the dual alternators no mater what engine you have.