AI agents can change a system quickly. That is powerful, but it also means a builder needs a way to keep the work grounded. Git gives every experiment a checkpoint: what changed, why it changed, and whether the system actually improved once you look at the diff instead of trusting the summary.
On a real build, that matters immediately. A schema change can unlock growth or break your API. A new feature can make the system smarter or drain time on the wrong thing. A build branch needs to be stable enough to demo live, even while you keep testing better ideas on the side.
By the time a builder has shipped a real system this way, Git isn't just a tool they learned because engineers use it. It's the record of their thinking: commits, diffs, recovery moments, architecture notes, and the path from first working prototype to a system a real organization can actually use.