Performance
A measure of what is achieved or delivered by a system, person, team, practice, or service. In technical terms, it often refers to responsiveness (latency) and throughput.
Impact
Amazon found that every 100ms of latency cost them 1% in sales. Performance is a business feature.
Weinto take
Performance is not a bolt-on. You cannot "tune" a fundamentally slow architecture into a fast one. We design for performance from Day 0 (caching strategies, database indexing, asynchronous processing).