I think this new 'promotion' could lead to a lot of potential trouble, even conflict. If the app is charging, say, €15 and the meter is saying €20, the passenger will be happy enough the first time but eventually will start to think that taxi's have been ripping them off over the years. Get someone who's naturally cranky and/or drunk, and you could end up in a boxing match.
And I don't see how the app can be accurate with the way the council has set up the road system around Dublin. North strand/Fairview is a disaster, half the city is gonna shut down next week because of Biden and the ESB are warning of complete chaos over the next few years as they dig up every second road in Dublin to upgrade the electricity network.