As the article says it is common in Cork & some other areas but it has been done away with in a lot of the country already.
The main difference for a builder is in funding their cashflow on a development. A builder with stage payments generally doesn't need to use as much of his own funds/bank finance as one who doesn't collect stage payments. So when stage payments are done away with a builder/developer usually has to secure more finance to build the development. One of the ways they deal with this then is to build in smaller phases.