Like all slide rules, the CRP computers will do conversions much quicker and easier than a calculator...
When you are next shopping in foreign parts, set the value of the Euro (or whatever) on the inner scale, hold it in your hand while looking at the items on the shelf and you can read off the exact price in real money instantly. With a calculator, you have to punch in the shelf price each time to get the answer. With a slide rule, you just look and the answer is there.
I can't imagine ever selling my CRP while I'm still flying.