I've never used the curse-client myself because I've got no problem manually installing my add-ons and not having issues, but from what I understand, it isn't the client that carries the keyloggers, but the addons you choose to download with it very well may. When I download and manually install add-ons, I know there aren't any .exe files included, but supposedly that isn't the case with the curse-client as well as other add-on managers. Regardless, there's no excuse for not having an authenticator, and if you lose your accounts or your items, it's your own stupid fault somewhere along the line.