I think they're trying to enable "introverts," give them confidence and an icebreaker to approach people around them. Your solution, "put away your phone" is easier said than done, especially for introverts. Personally I hate being glued to my phone in public as many people are, because it reminds me of how far apart people are by using their phone as a crutch to not interact.
Its hard to predict how color might affect an outdoor street atmosphere, but their goals are admirable.