Your second example misses the auto-growing part. Sure, I want an array, but if that becomes too small, I automatically want to realloc the underlying data to a larger array. And I want to use it for Foo, for int and for any sized objects, generally.

C++ can create the proper zero-overhead abstraction over it by generating code for each type I use it for, C to my knowledge can’t do so without copy-pasting code or doing things with runtime overhead, resulting in (often) much slower code.