Earlier quoted context omitted.
Not the OP, but the most likely reason I can think of is manual payments give an opportunity to review all charges. But still having the minimum set to autopay ensures that if you forget or unable to, the consequences are less severe.
But if you're going to check it every month anyway, why have the backstop be the minimum payment and not the full payment? You don't lose the right to dispute a charge just because autopay paid the statement off, and setting it to pay in full means you won't be charged any interest at all if you forget to check one month.
A pending fraudulent charge on my credit card isn't a problem. Cash missing from my bank account until the investigation is complete CAN be a problem.