How does the commitment position market products?

Your questions asks about the commitment position and marketing products.  While the commitment position is commonly called strategic commitment, the concept includes competitive advantage, strategic positioning, and reputation building.

So, strategic positioning is a compelling, clear, and concise message that targets and accommodates the needs of potential buyers.  These buyers are strategically researched to align them to the list of product attributes or the product positioning.

Often, strategic positioning can lead to paradoxical paralysis for potential consumers.  An example of such paralysis could include two very similar shampoos, which have identical lists of attributes.  The paradox is that the consumer must abandon one choice to gain the benefits of the other. Yet both of the observable benefits are identical, thus leading to contradiction where both statements are true; however, one choice needs to be made.

The commitment position is able to market products by creating a dilemma where the buyer is pulled into the conflict of similar attributes for enough time to consider each product.  Then, the remaining decision is about the credibility of each brand.  Reputation building is the next marketing step.

All in all, commitment positions in marketing slow the targeted consumer long enough to, at best, consider buying a product, and, at worst, consider buying a product later. This, in turn, builds brand recognition and reputation, and may create such a dilemma that either the consumer buys both products immediately to comparison test each, or the buyer purchases the second choice later to compare attributes.  Simply put, commitment positioning creates a moment in the buyer's mind that plants a seed of marketing possibility.