(I work at Stripe on Radar.)
We see Chargeback Protection mostly as a way to prevent our users from burning too much founder attention doing chargeback management. Managing abusive use of the credit card rails, both by fraudulent businesses and by people attempting to defraud legitimate businesses, is something that we have substantial experience with. We have had years to tune our machine learning models; this both helps every user of Stripe (through blocking transactions likely to be fraud-y) and gives us the confidence we need to roll out a new product like Chargeback Protection widely.
We will, of course, monitor it during the rollout and adjust as we go.