It's natural, but there are doubts about its safety. In many countries it is still banned. And in countries like the USA it has only been available for a short period of time (after lots of lobbying).
In the USA it was available until 1991 with not a single medical case against it - and again since 1994 (simultaneously considered "safe" on its own but "not enough data to classify as safe" as an additive).
Not to mention, it has more than a thousand year of use. See wikipedia[0] about history and also the part of "controversy".
Unlike the egg/cholesterol and salt intake recommendations, which appear to be grounded in scientific incompetence, any concerns about stevia seem to be strategically managed by a competitor.
Stevia, the plant, is not new. Menacing industry in that equation is artificial sweetener interests that used government(s) to ban importation and ban the option to label stevia as a sweetener in the United States and elsewhere. It was still widely sold, bought, and consumed. Strains vary. Some have a bitter aftertaste. Some are bred to be mostly sweet with minimal aftertaste. Whether it's consumed as dried plant matter, ground, or as newer extracts, a wide sampling sifts out tasty, palatable strains.
> I am fine with it being on the market...
I'm fine with lettuce being on the market. It's smart to be skeptical about everything, especially on an individual level, and more so given your experience. I avoid artificial sweeteners, also. Not enjoying the taste helps.
Stevia is not artificial and has been used in Japan for decades. It is recognised as a mainstream sweetener. It's also used in Canada, for example, though not so widespread yet.