What is useful about a reference-to-array parameter?

Question

I recently found some code like this:

typedef int TenInts[10];
void foo(TenInts &arr);

What can you do in the body of foo()

Answer 1

One difference is that it's (supposed to be) impossible to pass a null reference. So in theory the function does not need to check if the parameter is null, whereas an int *arr parameter could be passed null.