I used to have a Carryout with a separate 12v power supply - the one the OP described has a 110v to 12v plugin adapter.
I eventually disconnected a step light and put in a water proof 12v connection.
The extra power supplied to the dish has a MAJOR ADVANTAGE over the coax powered dishes. Distance from the receiver to the dish can be a lot longer. I’ve used that setup with the trailer in the woods and the dish as much as 250ft away.
With the coax supplied power the 2017 model dish we have is limited to a 50 ft cable run. More than that the dish won’t work.
Now I do have to say that keeping two cables unkinked is a hassle. Most of the time (75%?) we did not need the extra length. I changed because the separate power dish quit working. A couple friends have repaired theirs by buying a replacement main board or a used unit on e-Bay.