The 200 extra jobs help safeguard the hundreds of jobs at the other three fabs at Leixlip. I think Intel's decision was whether to pull out of Ireland (gradually) or to invest for one more spin of the technology carousel.
If Intel had opted to spend the money in, say, China then the atmosphere in Leixlip would have inevitably have become downbeat as the fab complex would have been gradually running down...even if it took a decade to finally close.
As it is Intel has been getting very close to the European Union over the last couple of years and that together with the good fundamental R&D that Intel has been getting (such as the junctionless transistor) out of Ireland probably helped persuade the company to spend again in Ireland.
That and the excellence of the fabs it already has up and running there which I think won some sort of internal Intel competition in 2010.
200 permanent jobs isn't that much. However, it is hoped that Intel will generate significant amount of output at the fab and help boost the Irish economy. But then, corporate taxes are quite low in Ireland anyway - hopefully the Irish Government will get some revenue