The cost of swerving is very, very minimal (especially in a modern car that won't go sideways no matter what you do).

Imagine a two lane road with a car traveling toward an obstruction in its lane. The distance required to get the car out of the obstructed lane via the steering wheel is much less than stopping it via the brakes.

There's a reason performance driving has the concept of brakes being an aid to your steering wheel as opposed to being operated as a standalone system.