A saved state you can go back to when a run goes wrong. Claude Code makes one per prompt, covering files its editing tools changed. Git commits cover everything git tracks. Neither can undo a database change or a sent email.
An unattended run makes many changes before you look, so you need to know how far back you can go, and what that leaves behind. People find out that files changed by shell commands are not covered at the worst moment.
Say it to your agent
“Commit before each step of this, with a message saying which step. Don't run migrations or anything that touches a database or external service without asking me, since git can't undo those.”