I have used this location a couple of times for Wedding Photographs (with the permission of the OPW). It’s a lovely location, right in the heart of Dublin. It was greatly underused for many years - mainly due to the fact that many people never knew it existed. In more recent times, thanks to such events as Taste of Dublin and the Dublin Comedy Festival, many more people have become aware of its existence.
You can find some more information on this Heritage Ireland link