If a Camel unit ends its movement on a spance that is occupied by a Desert tile, the owner of that thile get 1 EP from the bank.
If a Camel carries 2 Camel and ends on a desert tile, the owner get 3 EP.
The more Camels end on a desert tile, the more EP the owner get.
Is it better than 1 EP??
I've played it both ways. "As many coins as camels" as a house rule is a lot of fun - it adds a lot of drama because it can swing the game.