Just that iterators is the API that C++ settled on for doing this in a generic way (well concepts in C++20, but I haven't learned that yet). It's totally 100%

Just that iterators is the API that C++ settled on for doing this in a generic way (well concepts in C++20, but I haven't learned that yet). It's totally 100% kosher to write a function that calls `.at()` instead of `operator+=`. As long as it only needs to work on vectors, strings, or other stuff with a `.at()` method. But if the function works on iterators instead it can work on ANY data structure that also fulfills the requirements of RandomAccessIterator API. String Views, raw pointers, a 3rd party Cord library, etc. There's no inherent meaning to the iterator API requiring `operator+=` instead of something closer to `get()`, except that it means that the iterator itself doesn't need to know anything about container bounds (like I said above, raw pointers work as RandomAccessIterators).