On by default. A channel listing rounds every view count ("53K views") and gives only a relative date ("3 days ago"). This reads each video's own page for the exact figures — 53,674 views and the real publish date — and adds the like count and description, which appear nowhere else.
It is also what the price turns on. Reading a channel listing is one request for up to thirty videos; the exact figures are a request each, and measured that is five times the cost. So a video costs $0.0005 either way and the exact figures add $0.0010 on top — $1.50 per 1,000 videos with them, $0.50 per 1,000 without. Turn this off for a cheap freshness check across many channels.
Every read that lands carries the exact view count, the like count, the description and the publish day. The publish time of day, the category and the keywords come only when YouTube also sends its player data, which it withholds from most datacenter requests; those rows carry the date as a day and say so via publishedAtIsApproximate. A video whose page could not be read at all keeps the listing's rounded figures, says so via viewCountIsApproximate, and is not charged the detail fee.