Which, while it is cryptic, certainly gives us a strong indication about the expected success of time-travel computation.

(Without MoRverse) It reminds us to consider the implications of physics and the evident time travel mechanism. At the simplest level we can ask ourselves "What is more likely? We derive the right result or we get eaten by a black swan while trying?"

A consideration to make with respect to Harry's experiment in particular is that what we discovered was only that it is more likely for Harry to panic than for Harry to solve that particular computational task via that method. Not enough to rule out some degree of shortcut taking but certainly enough to be rather careful when taking it to the extremes of brute force decryption.