I would have laughed heartily if it had been a funny joke.
I'd rather buy a UV lamp and sit under it once a day for about 20 minutes.
The current literature on VItamin D suggests that full skin exposure to natural sunlight is sufficient to produce AT LEAST 10,000 IU of Vitamin D endogenously.
Beyond all of that, as a rule I am more comfortable with a substance that endogenously produced (and therefore regulated by my natural biological mechanisms) than taking a supplement. Evolution has crafted the body pretty well, so I prefer the natural system over the artificial one.