If you have 2FA enabled on your Dropbox (and probably your email too), then taking just your credentials won't give the attacker access.
Also, an attacker logging in to your Dropbox would leave a trace in your activity log.
Also, an attacker logging in to your Dropbox would leave a trace in your activity log.
Of course, it's up to 1Password to decide whether those scenarios are a high priority or not.
edit: 1Password, not Dropbox