Visa transaction can be reversed back in up to 6 month. Bitcoin transaction cannot be reversed after one hour.
If you accept visa, you are forced to work on the trust for up to 6 month. In Bitcoin you are exposed for one hour. That's it!
In going forward discussions – let's compare apples to apples. I refuse the argument that Visa is faster. Faster doing what? Crediting your balance with the funds that can be reversed? Ok!