This tool lets members of a group contribute money without other members of the group knowing how much they contribute. But, it lets everyone know how much of the needed money has been contributed.
For example, the members of John's Bible study group want to contribute $500 to the ministry of Joshua in Jersey, but they don't want each other to know how much they each plan to contribute. Jerry, who is wealthy, doesn't want to look like he is showing off. Janice, who is just making ends meet, doesn't want to be embarrassed by the little amount she can give. And Jay isn't going to give at all; he'd prefer to give to something else.
So, they use this tool, and everyone knows when they've reached $500 and nobody knows how much another person is (or isn't) giving. Then they all - separately - send their money to Joshua's ministry account and nobody in the group knows anything they don't need to know.
But when you give to the needy, do not let your left hand know what your right hand is doing, - Jesus (Matthew 6:3)
“If God give thee not only earth but heaven, that thou shouldest rule over sun, moon, and stars, and have rule over the highest of the sons of men, it would not be enough to satisfy thee, except thou hadst God himself.”
–Jeremiah Burroughs, The Rare Jewel of Christian Contentment