The overwhelming majority of keepers don't use UV. None of the big breeders use it. UV is primarily marketed to the small scale keeper willing to pay a lot of money to vets and pet shops for unnecessary paraphernalia and garbage information.
The "the studies show they need UV" story is based on very short term studies which show that the blood chemistry changes if they're given UV. Yes, that's true, but the long term real world empirical evidence - countless keepers around the world keeping zillions of them for many decades and consecutive generations showing there is no practical difference, tells a different story.
Years ago I experimented with heliothermic species (such as diurnal skinks and monitors which spend most of their active time in sunlight), and even in those species, when kept side by side long term with and without UV there was no difference.
No one makes money from you if you don't buy anything, so there's a push to talk you into buying stuff. In over 30 years of working with reptiles I've never seen UV observably help pythons, but I've seen it harm them many times.
