This is an interesting device that may be helpful for some people who have trouble walking, but not standing.
I've seen several of this device,
The Alinker, at Disney World.
It's a non motorized, no pedal walking bike. It meets the Disney size guidelines for wheelchairs - measures 30" wide and 45" long. The only limitation I've seen is that it may not turn very tightly
One was a woman at Animal Kingdom; she had a shirt on that indicated she had MS (Multiple Sclerosis).
I don't know why the other person was using it, but I've seen photos of people with prosthetic legs, MS, CP and other conditions that affect stamina or balance. The first article I saw featured Selma Blair, who has MS.
This is a link to an article about a young woman with cerebral palsy who uses an Alinker.
And this is a photo from her article.