Actually this thing is quite useful for device automation (in factory) or system monitoring (aka SCADA).
It is an alternative for PC/104. So yes, this pc is useful and is still in use especially for Human-Machine-Interface (HMI) or any of the "not so critical" task (eg: flood gate control, traffic control etc...).
From my experience, i would say such system normally run on MS-Windows (CE, XP embedded) and pretty overkill to run Linux.
Who need the gorgeous 64MB when you only need 8MB ram

Btw, here is another smaller "computer" :
http://www.wired.com/gadgets/pcs/multimedi...allery_tiny_pcs