Now the Wall Street Journal has reported the 2017 flagship will feature a dedicated side-mounted button to launch Viv according to people "familiar with the matter". The WSJ has cited the same sources as saying current prototypes of the phone include the button, but they have said they're just as prototype stage and could change.
If the Galaxy S8 did have a dedicated button, it could remove the need to wake Viv up with a voice command, like you have to say "Hey Siri", "Hey Alexa", "Hey Cortana" or "Ok Google". Although there may still be the option to use your voice if you need to be hands-free, in the car for example.
Samsung knows it has to pull out all the stops with the Galaxy S8 after the embarrassment of having to end production Galaxy Note 7 due to several faulty devices overheating. It's been claimed Samsung may take its time in developing the phone and may skip its usual unveiling at Mobile World Congress, instead opting for an April launch.