I have only recently used Lyft with discounts or promo deals. I don't need it enough to use it otherwise and it really is more for convenience like needing to get to the airport at 5am or back from a bar downtown without finding a bus.

My data would probably throw off the driver if they see that I paid $20 for a ride that should have been $30. The rider pay may vary on if I tip based on the actual vs discount price of the ride or other elements too.

I think the metrics they are providing are potentially more useful if the driver is able to ingest and use the data but it's likely Lyft isn't 100% honest with their presentation or made this change to benefit their business over the drivers.