If you mean in terms of security of your agencies logins and passwords then it's pretty secure:
your logins and passwords are stored locally on your hard drive only.
Besides, you can use the master password option for extra security: your login information will be stored on your hard drive in encrypted form (AES256 cypher) and it won't be possible to decrypt them without your master password.
So generally speaking it's as secure as working with agencies directly using your browser.