We have been chronically undernourished in what sunlight provides for us, since humans moved from the wild world of mother nature to living and working in boxes all day. We have also moved away from the hormetic benefits of uncomfortable temperatures that our ancestors encountered without effort.
You don’t need any devices to fill these key needs of the body. Just go outside. There’s plenty of sunlight and hormetic temperature experiences for the human mammal to live a robust, healthy life.
HOWEVER . . . with modern living comes work schedules, kids, technology, and more that prevent many people from being able to just go outside.