I can think of one. Whether it is right or not is another matter :)

There would be times when you wanted to return to your position in the hash. If the iterator (or hashkey pointer) was reset everytime the program left a control loop, you would have to save it in a variable and then restore it each time you went into another control structure.

I don't see this as being a bad thing - other languages do it like this. I also don't know why it wasn't done this way rather than the way it currently is.

Having said that, I have found this to be a problem before, but some careful data structure design worked around it just fine.