Due to the extent of Church operations and the ongoing costs, they feel it is wise to save for a rainy day (as they also advise others). More details in my comment elsewhere on this page.
Having lived through the dot-com bust, my wife and I around the same time (20+ years ago), began to set some funds aside for the "rainy day" of not if, but _when_ I might lose my job in tech, given the often volatile nature of the industry. We've been fortunate not to have to need to dip into those funds for that purpose over that time, but I think it's a wise practice, one that the church teaches, and follows.