If the hash values are references to the array elements (not indices), then even if I shuffle the array, I can still find the correct array elements directly through their hash keys. The references to the individual elements of the array don't change when the hash is re-ordered. The indices do.
Examine what is said, not who speaks.
"Efficiency is intelligent laziness." -David Dunham
"Think for yourself!" - Abigail
"Memory, processor, disk in that order on the hardware side. Algorithm, algorithm, algorithm on the code side." - tachyon