Yes. The work to assert each pointer passed into a function isn't "high"; it's purely mechanical, it could almost be refactored automatically. But most of all, the effort required to prove you don't need to is _way_ higher.
I thought so too, for many other things, and did so too in practice. Then I was doing thousands of little tasks in order to improve "security" and "correctness" and "proving everything", and never got to actually do anything useful, and my code became bloated to the point it didn't get to do much useful work.
Now I'm more considerate, trying to weigh everything in the larger context, is it REALLY required to get my job done?