Pushing to GitHub is not a full backup of your entire computer — it’s a backup of what’s in the repo (and only what you committed). System backups (Time Machine, disk images, cloud backup) still matter for photos, app data, and anything else outside the repo.
When you clone a repo, you get full history locally. If GitHub vanished tomorrow, you’d still have commits on disk — that’s the “distributed” part of Git. For important work, keep a clone on more than one machine or remote when you can.
Secrets in commits (API keys, passwords) are forever in history unless you rewrite history — painful. Use .gitignore for build artifacts and env files, and never commit tokens. (Coffee’s Key Vault exists so keys live in your browser vault, not in a pasted commit.)
Practical stack: