The idea is nice behind this application (and its not-so-bright brother, Unity). However, I have found myself creating tabbed applications time and time again because the settings are not saved.
I just deleted an app I have created about 20 times already, added the tabs, logged and quit to see if it would restore credentials. The app launches and it shows ONE empty tab. This is frustrating beyond belief.
There is an app in Safari that allows you to create tabs "Tab Space". I think that works better than this apps. I get Coherence and Unity with Setapp, am uninstalling them and never using them again.