Simply put, henna art is not a tattoo because it is not permanent. It is a stain on the skin that wears off with time. The term “henna tattoo” has been put into use only as a marketing term; though the terminology is incorrect, making something seem permanent when it is not.
Henna art is art on the body just like tattoos yes, however, henna art is not permanent. It wears off over time while actually ink tattoos stay with you forever. Ink tattoos use a needle to penetrate the skin while henna art uses natural products and a piping cone to decorate the skin leaving a stain that will wear off in about 1-2 weeks time.
Henna art is just that, art stained on the skin. While an ink tattoo penetrates the skin leaving a lasting mark, whether it is wanted or not. Get rid of the incorrect marketing terminology and take henna art for what it is, stained art on the skin.