Well, I've seen the latest video of their platform and yes it is so simple to understand because we/you have the choice of what you want to do with the change. This is the link where I've seen the video
https://www.youtube.com/watch?v=QJxjZKIDxXA.
I've seen the usability of their POS. It's easy to use and no hassle when it comes to transactions. Is the all in the video already working or just an prototype?