Ryanair abolishing checkin desks means a saving in costs for Ryanair, but a loss of revenue for the airport.
The 'Even better' part in my post was to show how an airport owner / operator could see this change as an opportunity and make some money out of it, rather than seeing it purely as a loss of check-in desk rental income. The extra rental income from the retail units should at least decrease the need for airports to raise their fees, so one could argue that fares might not increase as fast as they would do otherwise.
Whether extra retail shops in a departure lounge is a good thing for passengers on environmental grounds is worthy of a completely separate discussion.