They specialize in telling confused corporations how to use voice mail. All this means is technology is subject to human frailties. The telephone answering machine quickly became a call screening machine. Fax machines soon became targets for junk mailers. Cellular phones make users instantly available, but few users give out their cellular phone numbers.
People use technology for their own convenience.
Voice mail is no different. About 75 percent of America's big businesses have voice mail. Smaller businesses are rushing to follow suit. Your old surplus 8088 computer with the addition of an insert card and modem can be used as a voice mail system. Voice mail can be a boon.