The idea is that coffeeware in itself wouldn't justify paying for it monthly but provides a lot of value on a per usage basis.
I conceived this pricing strategy for dnspager while pondering how to set its cost. Generally, alternatives exist, frequently integrated with additional services. Currently, I have no use for those extra services and would not subscribe to this one either, considering I might need it once every five years, approximately.
Is this a practical business model? Far from it, yet it strikes me as a reasonable approach to pricing this tool, and I find it very amusing.