There is no money to be made in show obedience or agility. A piece of card, rosette or less often a small trophy are the only rewards. It's done for pleasure (hopefuly both dog's and handler's) and is hard, but fullfilling work. My former trainer sts out at 5am or sleeps in a tent working in often muddy fields through pouring rain.
Two of mine, Izzy and Joly, love obedience work and would jhave liked agility, but I'm the sticking point, there.
Many cavaliers do and enjoy agility, but it's not recommended until the dog is 12 months old (later for larger breeds) because it can damage growing tissue.
Barbara, Monty, Joly and Teddy.