I've been using 2-factor log in for Gmail for a couple years now. I do have my home computers set up to bypass the authentication, but any other computers I do the 2-factor on.
A 2nd recovery email isn't the same thing. Two factor authentication is all about making it much more difficult for a hacker gaining access to your account. You log in normally then Google sends a message to your mobile phone. Then you either enter the code they texted to you or authenticate by hitting a yes button on the phone. This system is almost foolproof, but there have been cases where a hacker will 'hack' the users mobile phone and forward the number before trying to compromise the account. I'm not paranoid enough to think anyone would ever go to that extreme for what is in my email.
A secondary recovery email is something you have set up also. If by some chance you get locked out of your account, then that email comes into play. That is more like the hidden door key under the boulder in the back yard.
If you use any online service that offers 2-factor authentication it is likely wise to use it. It is also wise to not link all your accounts together, so if one ever somehow gets compromised, they don't gain access to them all.
It is good to be safe, but for most of us the likely hood of hack is a lot like getting struck my lightning, very unlikely.