Relay is just an automatic version of manual disconnect
You know what kills a diode style isolator
Starting up the engine and taking off down the high way with a low battery
The battery is drawing all the amps it can take, which may be near or even over the rating of the diodes
10 minutes at idle while breaking camp, will help reduce those failures
But I'm curious
Most diode failures, result in open diodes, like a blown fuse
If this happens the camper can not drain the truck battery
You would need a shorted diode to drain the truck battery
How ever an open diode to the truck battery, would mean the truck battery got discharged while driving to the campsite, instead of getting charged