Obviously there is ALWAYS a use for it, 64GB is petty amount of RAM compared to some super servers that people like IBM and Google have, some of the 'super' servers hold PETA bytes of RAM let alone Giga Bytes. Some examples:
"The record-breaking Altix 4700 system is now installed in Munich, Germany, at the Leibniz Computing Centre Munich (LRZ). LRZ houses Germany's National Supercomputer System, and the Altix 4700 installation marked the completion of LRZ's Phase I deployment, which incorporates 4,096 Intel® Itanium® 2 processors, 17TB of global shared memory, and a 330TB SGI InfiniteStorage solution.
The LRZ system, known as HLRB II, operates all 4,096 processors as a unified platform that enables applications to directly address all 17TB of memory."
IBM's Blue Gene:
"The archetypal Blue Gene/Q system called Sequoia will be installed at Lawrence Livermore National Laboratory in 2011 as a part of the Advanced Simulation and Computing Program running nuclear simulations and advanced scientific research. It will consist of 98,304 compute nodes comprising 1.6 million processor cores and 1.6 PB memory in 96 racks covering an area of about 3000 square feet, drawing 6 megawatts of power."
As for who needs 64GB... no 'Home Office' user that I can think of needs that amount really, but a server could easily consume that.