This can be looked at in two ways , but I do know I have done several check rides in the US and one of the 1st questions on your oral is " Where is the money ?" . The other reason for this is that if the DE turns up and you have not complied with the requirements he is still entitled to charge you . I dont think many people would want to cough up cash for nothing .
The other is self explanatory , big issue with this DE is paperwork takes forever .