Power BI? Never heard of it… till you mentioned it.
Looks interesting, I pulled it down, installed it and had a play for a few hours… Interesting indeed.
As you say, it is a very different beast. My very short take away, Power BI is for managers, groov View is for operators. The other big factor is that Power BI does not seem to be optimized for mobile (or web browsers) at all.
There clearly (in my mind) is room for both… Which brings us to your next set of questions… How to get data from EPIC to Power BI?
While there a lot of data connectors in Power BI, sadly there are no RESTful or MQTT connectors.
The most obvious next choice is MSSQL or MySQL.
At your central HQ location, run EPIC with groov View for an overview of your remote sites and Node-RED for pushing each remote sites data into a central database. (See my answer to your other question about VPN vs MQTT).
From that database Power BI can then pull any reports that you feel inclined to generate on the sites or as a whole.