I still don't think RPN is more logic - you have to break down expressions into fragments with RPN. HP probably just wrote that blurb because it's easier to do RPN than a complex expression evaluator

I agree...And the idea of the RPN saving keystrokes is rubbish as well. After each number you hit enter, then after the operator you hit enter. So for 2 + 2 = 4 you end up with 6 keystrokes vs. 4 w/ a standard calculator. Now for a much more complex equation, you still hit the enter after each keystroke, and unless you have a great many nested sub-equations requiring several Parentheses in a row, then you really loose keystrokes. Even in those situations it is not as much a savings as you are led to believe.

Another point to argue is the more natural method as taught in school on paper. I don't know what school(s) they are talking about, but I know a simple algebraic calculator allows me to enter the equation EXACTLY like I was taught in school.

The only "advantage" I can see is seeing the intermediate steps, but even this is trivially completed with a standard algebraic calculator.

So back to the original question - Why RPN?