Also seems convenient because you can have more than one cabin per shaft. But I'd suggest putting floor selection outside of the elevator if you do that so the cabins can be organised in a way to let you through before the ride otherwise cabins might get in the way. I'm also guessing this uses way more energy than a conventional elevator. It's moving a cabin up alone vs moving a cabin up and a weight attached to it down i.e. just speed changes and overcoming friction plus a bit of lifting maybe.