It's because "artificial" sounds scary. If you think about it, nobody would use "artificial" for branding in any other context.
And it's not like this is a new term, it's been used for 70 years now.
To be clear, I think most marketing is dumb. But avoiding the word artificial isn’t completely random.
Maybe not completely random, but it is pretty stupid. It's not a scary word, not unless you're afraid of nearly everything around you in modern society. Every bit of technology and construction around you is artificial.
People have artificial valves put in their hearts. Artificial retinas are a developing technology. Artificial joints have been a thing for decades. Homes have artificial stone and wood, for facades and flooring and other things. Rings have artificial diamonds. So scary.