I am of the opinion that a person should be able to use both interchangeably
Why? About the only people left who use Fahrenheit are Americans - everyone else has been managing quite happily using Celsius for decades. The rest of the world should now relearn an anachronism to keep Americans happy?
you can remove bike pedals with a crescent wrench, but why would you do that if you had access to a real pedal wrench?
But to follow your logic through, you're essentially telling people to carry two single-function wrenches, when one multi-purpose wrench would do just as well. Both wrenches achieve exactly the same result, but one can be used for purposes other than removing pedals. Why carry both?
It does rather sound like you are trying to justify your sentimental attachment to the system with which you are most familiar, rather than accepting it as an anachronism and moving on. I mean I get why that might be hard to do, and there's nothing wrong with being sentimental, but let's call it what it is.