So the phone then runs in it's own mobile data in parallel to the Hotspot. Thanks Madd62!!Welcome to Android Central.
The phone itself will continue to use it's mobile data alongside any device you are using from it's Hotspot. I have no home wifi and run 2 pc's, one mainly for You Tube or other streaming.
It cannot be signed in and connected to it's own Hotspot output.
Is it some security concern?