The problem with password managers is, when you're away from whatever machine you managed to get the thing set up on, you're locked out of all your accounts.
This way, you can access your passwords from home, work, or your phone as long as you trust the machine you're logged into enough to log into DropBox and type your password safe password. If you can't tell if the machine is free of keyloggers, you probably shouldn't be logging into anything of personal value.