I understood from the start that this data was for fraud protection. At the time of my initial article, Stripe had not clearly disclosed the extent of their tracking nor stated any limitations on how they would use the data. I tried hard to avoid accusing Stripe of nefarious behavior, so if there are specific sections in my post that failed to do this, please let me know.
Regardless of Stripe's intentions, I believe there needs to be clear agreement about what data Stripe collects and what limits they'll observe in using that data. If we blindly allow Stripe to collect whatever data their JS library has access to as long as their intentions are good, we put ourselves at risk if that data falls into the wrong hands.
I think Stripe shows a serious commitment to privacy and security, but there's always an inherent risk in storing copies of data with a third party. The more data that Stripe collects, the greater that risk, so clients should have a say in whether that increase in risk is worth the improvement they receive in the accuracy of Stripe's fraud protection.