Definitely. While it's not a perfect solution, it provides an extra layer of protection for your accounts by making an extra hurdle for any attacker to clear. Needing two components to access/change your accounts is elegant and effective.

Pay-as-you-go phones are advisable to use for two factor verification, as they are affordable and could be used only for this purpose. Don't hand out the number and you've got a nice disposable tool for protecting your accounts.