Not to defend C strings too hard, but it does make some sort of sense, IMO. You have to manage all your buffers manually in C, whether they contain a string or not. If you store a string of length 5 in a 10-byte buffer, you still need to manage the 10-byte buffer. Raw pointers kept things very flexible and lightweight when C was created.

Nowadays, things like C++ string_view's and Rust str slices handle this for you automatically, but those came around much later and require more sophistication at compile time.