Language exists in this medium - language that computers cannot mimic or understand the way humans do. There is also intonation, pauses, etc.
And concerning the computers ability, a computer can capture microexpressions that we may miss by looking away to collect our thoughts or to remember something, etc... Computers can do this now, and there is no reason to expect this gets worse. As someone who is likely on the spectrum, I look forward to the day when a computer can tell me when people are bored of me talking to them. I'd like that very much.
Yet.