Every time you rely on the current working directory, that's invisible state then. Even without multiple single-letter directories each maintaining their own state.
(Really, people don't engage more with physical machines to consider programming. We insist that everything has to be distilled down to symbolic functions. Preferably limited inputs and a single output. If only life was so accommodating.)
`CD` without any arguments will display the current directory on the current drive.
`CD E:` will display the current directory on the `E:` drive.
No state chnages for either case.
And you think adding to it will improve things?
But a lot of times, you also need to think about executing programs from within a script, where you don't have this prompt. Thus, it's invisible state.