I really don't see the point of this, except as part of a development trial (or a gimmick). The article says:
“When fully operational, each bus will have a driver monitoring the system alongside a bus captain who will help passengers with boarding and buying tickets.”
So it's not really fully autonomous, and they’ve replaced a driver-operated bus with something that requires two staff on board? Difficult to see any economic benefit in that once the government’s financial support runs out. And why do passengers require an additional person to help with boarding and buying tickets, on every other bus in the country that's the driver.
One of the articles linked from the main article suggests that the major benefit is expected to be improved safety ... so do Scottish buses have such a bad safety record that this is a better option rather than, say, improving driver training?