There are many reasons: 1. They want the distribution effect of the app store. You can go from zero to king overnight if the app store features your product.

There are many reasons: 1. They want the distribution effect of the app store. You can go from zero to king overnight if the app store features your product. 2. Unless you're building a dumb wrapper around a CRUD backend app, most apps need access to the state of the art API. Especially if you're aiming high, chances are, you won't be able to find a new app idea without using the new APIs because the old APIs have been experimented on by millions of developers already. 3. Apple has declared recently that they're going to cripple the browser localstorage and cookies so everything gets reset if you don't use them for 2 weeks. I think they will do this more and more (it's also good for user privacy so they do have a moral high ground)