I've not used one myself but have seen a few of them around The Netherlands over the past 10 or so years. They don't seem very popular but I think for a very narrow group of people they work well. There are also two wheeled balance bikes for adults that I think have been around for decades. One problem with balance bikes is foot/ankle pain. I've no idea if that would be a problem with the Alinker or not.

Most older people in NL and other nearby countries ride regular bikes (Dutch though, not what Americans consider regular), or step-thru or trikes. And if necessary carry a walking stick or crutch.
https://streets.mn/2015/05/06/enabling-the-disabled-a-view-from-the-uk/
https://www.ableamsterdam.com/blog/mobility-aids-in-the-spotlight-a-review-of-the-alinker