1. It's often surprisingly difficult to fire an underperformer (anecdata: a friend of mine has lost multiple talented members of his team in the past few months - all the result of having to work with one completely unqualified person. For some reason, the other person has not been fired). As a result, a bad hire can have an outsized and lasting effect on a company.

2. Unless you're looking at very senior positions, there are almost always more people available to fill a role. You may miss 9 out of 10 people who would be effective in the role, but you only need to hire one person.

The math changes a bit when you look at the mythical 10x developer, so maybe it would be worth looking into false negatives specifically in that case. Still, getting that 10x dev would be much more important in a more senior position.