For mobile apps, to pass the app stores' verification. iTunes doesn't allow applications to exclusively depend on other applications to run. As a consequence, asking users to "sign in with an external DID wallet" to continue inside an app is forbidden. Because of this, mobile apps willing to be published on iTunes need to use the local identity connector to let users choose whether they want to use a built-in / auto-generated / temporary identity or a real identity from an external wallet, such as Elastos Essentials.