I was playing around with Data Flows myself. I think this is a key move because it separates the ETL that was embedded into your PowerBI document, into a standalone function that creates governed simplified data that is accessible to all PowerBI users.
The problem I found is the PowerQuery in PowerBI online has significantly reduced functionality from the desktop version. For example, I couldn’t find any way (without writing your own M code) to simply tell it a column that comes over as Text is actually a number (because of the totally broken way Epicor has configured BAQ’s in both the V1 & V2 implementations). All data from the BAQ’s comes over as text and you have to use the Powerquery tools to convert into numbers, dates etc.
The only workaround I found was to do all the work on PowerBI desktop. Then go into the ‘advanced mode’ that shows the ‘M’ that gets created. Then literally copy and paste that into PowerBI Data Flows advanced editor.
Epicor still needs to fix the way they publish BAQ’s in order to not have to create a separate connection for each query which is slow and clunky for projects you create. You should be able to establish one connection (like you do with SQL Server) and then pick the ‘tables’ which should be each individual BAQ.