I know of some breeders that use the ambient heating method. The theory is they are following the natural tempreture cycles of night and day. As long as they are in their required range most should do fine. I bought a pastel from a guy many years ago that used that method successfully.
What is reccomended alot on this forum is for beginners, its not the only way but its much safer and easier to achieve for the average beginner. Most folks cant provide a perfectly climate controled room so you wont find that reccomended much.