That is how it is always done in these parts. If the wall is above grade, it is framed. Concrete requires different insulation, harder to work with, more expensive etc. Now ours was 2x6 to support the 2 stories above - the rest of the house was 2x4.

We have a front wall - all concrete, side walls stepped down toward the back with the concrete, and then a small corner of the back wall had concrete - never did figure out exactly why.

We've owned two houses with walk-out basements. The way David Cary describes it is exactly how ours were built.

That is how it is done in Michigan. If it is in a colder climate they will also have to have a frost footer. Here it is 42" below grade and also has to extend 5 feet on either side of the walkout. Also when they pour the basement slab they have to put down foam around the walkout perimeter.

That's how ours is as well (in Illinois)

Illinois...our last house was the same.