Not so simple. Being a good calculator is sometimes a good prerequisite for other kinds of thinking. Or, at the very least it makes some tasks easier. I have a lot of students that come through my laboratory. As part of their training it is necessary to do some algebra and arithmetic fairly regularly. I typically bar calculators, because I see them as a mental crutch. Being good at calculations is a good proxy for being able to integrate complex thoughts all at once and do something useful with the information. If one can do a multi-digit calculation without the aid of a piece of paper or a calculator, I think it shows that one is able to keep several things organized in one's head simultaneously (as place value calculations are accomplished most easily by doing several simple calculations which are then combined linearly). Maybe I'm nuts and/or old fashioned, but I find arithmetic to have a lot of value (so long as we consider it a means and not an ends).