It is useful: When iterating over a string in Python (which I hope you agree _is_ useful?), you get that many parts.
That’s… not useful?
I can’t say I remember ever caring knowing how many items I would be getting during an iteration[0]. If I want to set an iteration limit I can just… do that, using `islice` or some such.
[0] in python anyway, in lower level language there can be a utility in order to pre-allocate an output collection
Not often. There’s almost nothing useful you can correctly do with a sequence of code points.