It would be useful in some contexts but I wouldn't want to abandon street names and house numbers for it since they do make things easier when giving directions (something like "Take a left at N47°26'39.4 W122°18'03.8" would get out of hand quickly, especially over the phone) and it'd be strange to display something that long on the outside of your house instead of a 3-4 digits.
It may have changed, but last time I was there, most of Ireland outside of Dublin had no addresses, just coordinates. Navigating wasn't too hard though, streets have numbers, and directions were usually a "turn left at road 1310, etc.".
It also helps that most of Ireland is pretty rural.
