Tone, intonation, and pauses add color to the language, and are by no means required. Think of them like spices, which add to the flavour, but not to the nutritional value or substance of the language. I have never had a thought I couldn't express with written words. Tone, intonation, and pauses can round out a story, or make communication slightly more succinct, but language exist both with and without these. And again, these are not required.
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.