One difference is you see all intermediate results. That's huge for avoiding mistakes. In-fix, if you type (5+5)*(9+9), you only see the end result. Post-fix 5 5 + 9 9 + *, you see 10 and 18 along the way.
Another is the stack lets you easily reuse subresults. If you've computed the total energy and want to use it three places, you pick it off of the stack. All your work is there. It's very common that this happens.
It's an incredible productivity boost once you get used to it.
It gets even better when you tag numbers with the correct units. The calculator does type checking and automatic unit conversions. So if you key in the wrong operations, you'll either get an error somewhere along the way (from eg. trying to add something in m/s to something in m/2^2) or you'll notice the units at the end of the calculation don't match what you're supposed to end up with.
One difference is you see all intermediate results. That's huge for avoiding mistakes. In-fix, if you type (5+5)*(9+9), you only see the end result. Post-fix 5 5 + 9 9 + *, you see 10 and 18 along the way.
Another is the stack lets you easily reuse subresults. If you've computed the total energy and want to use it three places, you pick it off of the stack. All your work is there. It's very common that this happens.
It's an incredible productivity boost once you get used to it.