It was before valgrind. Besides, valgrind isn't always available, it requires all code paths to be tested, and it can be really slow making it impractical for some code.

Default initialization, on the other hand, gives 100% coverage. Experience with it in D is a satisfying success.

May have been impractical to run valgrind eg embedded. A decent compiler should catch this anyway? -Wall?

Testing all code paths means all code paths must be available to the compiler. This is not always practical.