Ah and there is the ultimate question...
I'll tell you why those units used Wi-Fi ...
Because when they were devised "Wi-Fi" was a new, cool, exciting technology and had to be on everything - in much the same way today, everything, no matter how pointless is being done on a tablet everywhere, even though it's often ridiculously expensive, or functionality draining... it's the "in thing".
...which is the very reason my old boss tried to force me - back when 11 meg was the best you got, to fit wireless cards to all the sales team's desktops, then install a buffalo airstation. All despite them all already having cabled network connections in place and working.
There wasn't a single good reason - we didn't need desktops to be "portable", we didn't need the near 10x reduction in raw speed (ignoring the other limitations of multiple devices on one AP), we didn't need to spend all that money which at the time was a fair bit, but it had to be done because the boss had heard that Wi-Fi was the latest and greatest thing.