It's not so much that it's "more" in the sense of more of the same, like, e.g. requiring 2 different passwords. That's a waste of time. But 2FA makes the attackers job much more difficult. If someone steals my password or compromises a key, then they still need to hijack my SIM for SMS or steal my phone to get a code from my authenticator app. That's 2 completely different kinds of shenanigans that need to be successful.