Well, ball pythons in particular live in rodent burrows and termite mounds. Both of these hold constant temperatures even at night. Ball pythons do not go out during the day and "bask". They stay in hiding all day and come out for food when they are hungry.

It is really just for the health of the animals. They seem to thrive at certain temperatures and rarely get sick. Remember, you are keeping these animals as pets, they are not in the wild so you shouldn't try to replicate their natural habitat. If you did that, you would have to introduce more competition. It just isn't a good environment for a pet snake.