This is true. But, what I learned the hard way is if your destination is 5-6 hours away, your batteries will be pretty run down and you’ll have a hard time with the leveling system. To combat this, I’ve employed a couple different techniques.
First was to keep 7 way plugged into truck and plug in shore power before leveling
Second I discovered by accident. I forgot to turn on the inverter. 5 hours later, freezer had gone from 0 to 26F and fridge went from 38 to 45F. Of course I keep my trailer plugged in at home and the fridge is always on. So, unless I plan to drive for more than 5 hours, or it’s the middle of Texas summer, I don’t bother with the inverter. Otherwise, I’ll turn it on when we leave and shut it off midway at our restroom stop.