Commerce Layer is the commerce engine when the storefront is not a store. Content sites, apps, kiosks and marketplaces all need cart and checkout, and none of them want a platform dictating the front end.
We model markets, price lists and stock locations first, because that structure is what makes multi-country selling work rather than a later retrofit. Then we wire it into whatever front end the brand actually needs. It is the right call when you are selling in several markets. For a single-country store it is more machinery than the job requires.