In December 2019 I heard from Mathieu who had recently come across two CA5s tucked away at the back of a cupboard and decided to put them into service.
"I was able to happily put one of them back into service as a PBX running Asterisk on Debian Jessie, with an HDD attached like on your tutorial, and extra RAM salvaged from another oldie.
As for the second one, I have plans to turn it into a personal Squid server.
Debian Jessie will happily run on those machines, without a GUI of course. It's the last version of Debian with 586 support."
It is nice to see that thin client hardware from 2004 can still be pressed into useful service in this day and age.