Does setting up IFTTT cause existing Google Home setups to need to be redone?

[AC Question]

I already have Google Home using voice commands to control lighting, thermostats and video streaming (Netflix, CBS & Youtube) via integration with a SmartThings hub. Now I would like to add the use of IFTTT to integrate some other devices. When you sign up with IFTTT and start to use it, it asks you to allow it to "manage your google voice commands". My question is, if I proceed to allow then will I also have to re-do all of my existing setups or will they remain functional as-is and I will only need to add new integration commands?