My guess is that the term comes from the Wiener's cybernetics, dating from around 1950. It was used in pop culture in "Cybermen" from Dr. Who, and "Cyberspace" in SF through Vinge's "True Names" and Gibson's "Burning Chrome" and "Neuromancer", which lead to the cyberpunk movement.
As such, it's more been associated with social commentary and business and political philosophy and not with technical language. It become popular in general culture and political discourse in the 1990s as part of the popularization of the Internet.
I can therefore make a couple of conjectures. 1) it's dated, 2) it's viewed as an outsider (eg, non-Internet software developers) intrusion, and 3) politicians, bureaucrats, and other people in authority tend to use it to drive analogies between meat-space and cyberspace, like 'cyberattack' and 'cyber Pearl Harbor' when such analogies often seem stretched, and used to justify increased government influence and oversight of the internet.
Alternatives: Computer? Depends on the circumstance.
[0] http://threatpost.com/csi-cyber-we-watched-so-you-didnt-have...