Copy/paste M queries with dependencies from desktop apps into dataflows
Power Query, whether in Excel Desktop, Power BI Desktop, or Visual Studio, lets you copy/paste a query back and forth between query panes, and that single pasting will carry over all dependencies (if any), i.e. functions, parameters, and nested queries (via Combine or Append). This makes it very easy to migrate PQ solutions from Excel to PBI to SSAS/AAS.
My suggestion is to add a Paste action in the Power Query Online query pane, with the same smart behavior as in the desktop apps.
See this if you're not familiar with the desktop behavior I'm talking about: