You don't take public transportation in a big city, do you?
Cell phone theft is a HUGE problem. Huge.
People don't like carrying things of large, uncontrolled value on their person when they don't have to. The status quo is the equivalent of forcing people to carry a small brick of gold on them everywhere they go, just so they can hail an Uber or play Candy Crush.
People will literally feel safer for this every day - I know I do already.