A few years ago, I same across the archetype of this trope: a Star Wars action figure of a droid that came with a "data entry terminal" as an accessory. I don't remember which of the half-dozen movies this droid showed up in, but I do remember him clearly, standing in the background, tapping data into his terminal.
My first impression was that this was a classic example of Zeerust: why have a humanoid robot type data into a system, instead of just directly interfacing with the system?
Almost simultaneously, though, another thought struck me: Wow, that's one way to check the spread of viruses and malicious software.
Not quite so "quaint" from that perspective, is it?
A few other Perfectly Reasonably Explanations occurred to me later — it's easier to establish some degree of uniformity in user interfaces than it is in underlying code, for instance. For a while, my residence had a Macintosh, an Ubuntu box, and at least one Windows PC. They all had mice and keyboards and monitors, but we could never get their supposedly-compatible file-sharing protocols to talk to each other. Spread that across a Galactic Empire dealing with the patchwork remnants of a Republic, and see if you don't wanna just put a droid at a keyboard.
— Your Obedient Serpent, 17 FEB 2014