This is a software limitation of the device, technically there's nothing preventing the app to auto-update like on Windows. We could also imagine a mechanism t

This is a software limitation of the device, technically there's nothing preventing the app to auto-update like on Windows. We could also imagine a mechanism to provide an update URL in the app metadata. The OS could query this URL periodically to check for updates. So it's still a direct install, it's just that direct install support is limited on phones.