Why does the Airbnb style guide say that relying on function name inference is discouraged?

As any other style guide, Airbnb's is opinionated and isn't always well reasoned.

Function name property isn't supposed to be used for anything but debugging in client-side application because function original name is lost during minification. As for debugging, it becomes less efficient if a function doesn't have a meaningful name in call stack, so it's beneficial to preserve it in some cases.

A function gets name with both function definition like function Foo = () => {} and function named expression like an arrow in const Foo = () => {}. This it results in Foo function having a given name, Foo.name === 'Foo'.

Some transpilers follow the specification. Babel transpiles this code to ES5:

var Foo = function Foo() {};

And TypeScript breaks the specification:

var Foo = function () {};

This doesn't mean that named function expression is bad and should be discouraged. As long as a transpiler is spec-compliant or function name doesn't matter, this concern can be discarded.

The problem is applicable to transpiled applications. It depends on a transpiler in use and a necessity to keep function name property. The problem doesn't exist in native ES6.