iPhone and Android support I'm curious why a small kickstarter would want to build specific apps for each device. Is this critical day one stuff for small star

iPhone and Android support I'm curious why a small kickstarter would want to build specific apps for each device. Is this critical day one stuff for small startups like this and is there a real customer need for an app in a marketplace? Instead of just building a simple HTML5 site that'd work on all modern devices and browsers, that is.