C++ programmers decided against NULL, and for well over a decade, recommended using a plain 0. It was only recently that they came up with a new name: nullptr. Sigh.
That had to do with the way NULL was defined, and the implications of that. The implication carried over from C was that NULL would always be null pointer as opposed to 0, but in practice the standard defined it simply as 0 - because C-style (void*)0 wasn't compatible with all pointer types anymore - so stuff like:
void foo(void*);
void foo(int);
foo(NULL);
would resolve to foo(int), which is very much contrary to expectations for a null pointer; and worse yet, the wrong call happens silently. With foo(0) that behavior is clearer, so that was the justification to prefer it.
On the other hand, if you accept the fact that NULL is really just an alias for 0 and not specifically a null pointer, then it has no semantic meaning as a named constant (you're literally just spelling the numeric value with words instead of digits!), and then it's about as useful as #define ONE 1
And at the same time, that was the only definition of NULL that was backwards compatible with C, so they couldn't just redefine it. It had to be a new thing like nullptr.
It is very unfortunate that nullptr didn't ship in C++98, but then again that was hardly the biggest wart in the language at the time...