Well, I wouldn't say ridiculed, but I know people wouldn't plan on breeding these for money. It's just they are so easy to breed and are pretty common actually, that some people either have to give the babies away, or pay people to take them.
Every once in awhile you'll get lucky and be able to find a buyer, my LFS
decided to start buying from me once my breeding starts going, since it will be easier to get them from me then buying from somone else. Plus they know I will take good care of them, plus they are going to give be quite a bit for them actually, since they sell them higher price at their store.
If your looking to breeder something with a for sure money maker, I just wouldn't try convicts. I'm just doing it for the fun of it, but yeah do what you want. Just don't be counting on making money off convict fry.