A little clarification:
You can do admin on a mobile device; for now that means only while on the same network as your hub.
We do not intend to develop anything resembling the ST mobile app, which is the only way you can do admin for an ST system.
We do intend to provide in the future a remote access mechanism to the admin web interface for Hubitat, thus obviating the need for a VPN. I guess you could say, we will provide a mini-VPN to allow you to get to your hub's web interface. This is being tested internally at proof-of-concept stage -- that is, we know how to do it and it works. This mechanism will entail secure access and authentication.
So, combining the first and last above, it will be possible in the future to do admin of your system remotely using a mobile device. However, that will be via web access from the mobile device, not app based access.
Our mobile app is entirely off this topic, and supports dashboards, notifications, and mobile presence.
