Automatically adding untracked files would make it extremely easy to commit (and without other safeguards, push) unwanted changes. Annoying things like node_mod

Automatically adding untracked files would make it extremely easy to commit (and without other safeguards, push) unwanted changes. Annoying things like node_modules or binary screenshots that now bloats the repo history forever (unless one rewrites the history), or potential security breaches like passwords/keys or logs/configs with confidential information.