But that’s trivially false. There is an entire category of work where it is hard to come up with an answer and easy to verify the answer, which means that if you verified everything there would still be a large time savings.
But if you want to keep it in the realm of the everyday: you're asking if it is easier to write an email than to read it and check it covers what you wanted to say? Is it easier to search for something or to look at what's been found and say that it's what you were looking for?