But at the end of the day, it won't have any weight in the long run because these ponzis simply use bitcoin as a payment method and doesn't represent bitcoin in any way. The fundamentals of BTC's network and technology is what drives long term prices, not third parties
I tend to think it does in fact affect the fundamentals
And not because it adds to volatility (though it is about that too) but for the image that such use produces. Indeed, it doesn't change the technology behind Bitcoin, but technology without adoption is pretty useless on its own. When people lose their money via Bitcoin as was the case with PlusToken, their overall attitude toward cryptocurrencies changes and not for the best, to say the least
And yes, I know that the dollar (for example) is used for nefarious purposes as well and probably much more in general. But this use is still minuscule compared to its other uses, good ones, so it doesn't affect its image so much