Pythagoras: Well, you may be right but only from a long term point of view. For example, I need to purchase a new application server (or two to make a fail-safe cluster). The estimated price is, say, 3000 Euro. With 10 new Black Rooks I could buy it immediately and the site would be faster and much more reliable immediately as well (which is an undoubtful benefit for everyone and also brings a possibility to launch new services and enhancements without worrying about the site performance). With standard membership payments, I would have to wait for several years to accomplish the same deal. Yes, the final sum would be higher but the faster availability of the resources is more important.
Anyway, any help and support is always welcome, of course.