Who is using OS/2 today (in business)? What are the advantages over any other solution? Is it just about maintenance of legacy systems, or is there something new built on this platform?
There were news that in early 2000 it was still running the whole Hong Kong airport.
In Italy where I live, up to 2010 if not later, you could still find kiosks for buying railway tickets that were powered by OS/2. These kiosks were quite bulky because they had CRT touch screens! The CRT screens were mounted on a vertical rack inside the kiosk which had two axis, horizontal and vertical, and when you pushed the screen to tap a button the two axis would feel the pressure and would be able to identify the area of the screen that you pushed and to pass coordinates to OS/2 as if you were using a PS/2 mouse. Of course not as precise as a smarphone touchscreen, but those UI used fairly large buttons and everything was working perfectly.
In Italy I think I kept on spotting old ATMs running OS/2 until at least 2015.
I know of a large Bank, this time not Italian, that was still using OS/2 for its tellers probably around 2012. They were using a Web application already, but browsing it via a Firefox port for OS/2 https://wiki.mozilla.org/Ports/os2 They needed to do so because of certain legacy devices (cash dispensers, check printers) which only worked with OS/2.
The hobbes archive still recevies updates and uploads with os/2 software:
https://hobbes.nmsu.edu/ and https://hobbes.nmsu.edu/?path=%2Fpub%2Fnew
Edit: fixed URL
Only IBM has the full source code (and obviously they don't care much about OS/2), so the only changes made for the last ~20 years are binary patches, third-party drivers, and extensions. It's a 32-bit operating system and will never transition to 64-bit.
OS/2 now probably full of hundreds of well-known CVEs. So, any machine used out in the wild is trivially exploitable.