Wouldn't a better calculation involve (2^64 + 1) bytes of storage, or even 2^65, instead of going for the upper bound at (2^128)? In other words, what's the min

Wouldn't a better calculation involve (2^64 + 1) bytes of storage, or even 2^65, instead of going for the upper bound at (2^128)? In other words, what's the minimum energy requirement for 64 bits to be insufficient? A neat calculation for the wow-factor, but not really very informative.