Depends on what you would want to do with the babies.
If they would be pets, I dont think breeding pet store fish would be a problem...
BUT - if you want NICE fish that you could send to shows or sell on AB, you need to start with quality fish.
If the fish aren't worth it to the breeder to go anywhere other than a petstore, that means they are the breeders cull quality fish. You dont know the genetics behind the fish, so you dont know what will pop up in a spawn. You could have red fish and end up with a blue marble or something completely random.