I recently stumbled on a use for Duo - for elderly people that have not used smartphones before, the interfaces of other apps like Skype, Hangouts, etc. are ove

I recently stumbled on a use for Duo - for elderly people that have not used smartphones before, the interfaces of other apps like Skype, Hangouts, etc. are overwhelming. Duo's simple. It does only one thing. Good luck getting anyone who already has a preferred app to use it, though.