Large Language Models matter because they fundamentally change what software can do for people. Unlike traditional programs that follow rigid, hand-coded rules, LLMs understand context, interpret intent, and generate meaningful responses across an almost unlimited range of tasks, all from a single model. For product teams, this is not just a technical upgrade; it is a new design primitive. The question shifts from "what can we build?" to "what problem are we solving?" because the barrier between human intent and machine capability has been lowered.