Programming

What would be ELI5 use case of this? It has been almost a decade since I did anything math-formal in college, and I wonder what would be some practical uses or situations is SW dev where you should turn to this language.

EDIT: I skimmed the intro to Verifiable C, and I think I vaguely understand the idea - do I get it right, that the point is to basically create a formal definition of the function you are writing, i.e if you have a function that takes an array and sorts it, you'd have something like

For every sequence a and every i, 0 <= i < len(F(a)) -> F(a)~i~ < F(a)~i+1~

(Or whatever would the correct formal definition be, I don't really remember the details, I know I missed some stuff about properly defining the variables, but the idea of the definition should be kind of correct)

And then you define this formal definiton in CoQ, then somehow convert your code into CoQ code it can accept it as F(a), and CoQ will try to proove formally that the function behavior is correct?

So, it's basically more robust Unit Testing that's backed by formal math proofs?