They are constantly shedding Teflon into your food, even if you baby them with the softest possible utensils (which you need to do anyways to have them last more than a week). When people talk about microplastics in your blood/brain, this is one of the more common sources.
The field of understanding the impacts of having plastic in your body is still evolving, so there's little conclusive proof that it's bad for you. But there's definitely no proof that it's good for you either.
Also, if they ever get overheated, they can release toxic gases into the air, and given that most home kitchens are poorly ventilated at best, it's not good.
On top of all that, as mentioned, they're practically disposable dishware because the PTFE layer loses its nonstick properties pretty rapidly under any amount of regular use.