Performance Marketing is marketing that is planned, optimized, and judged primarily by measurable outcomes such as leads, sales, revenue, or qualified actions.
It matters because strategy keeps channels from competing with each other. When this concept is clearly defined, the team can connect budget, audience, creative, offer, tracking, and reporting to revenue instead of chasing disconnected metrics.
Example
An advertiser measures campaign cost against qualified inquiries and completed sales. If a cheap lead source produces unsuitable inquiries, the team can change allocation rather than treating low cost per form submission as the whole result.