Take for example 1Password, that now can store your password and one time password secret in a single place (your 1Password vault).
I know it isn't truly two-factor anymore, but how much better is it compared to single factor authentication?
To be more clear, say I have a Dropbox account with two factor authentication enabled, and I store both my Dropbox password and OTP secret in 1Password -- thus both accessible by one factor, my 1Password master password. Assuming I have a strong master password, and my Dropbox password is strong and isn't repeated anywhere, is there any security to gain from using two factor for Dropbox?