Adding a timestamp to your comment on a YouTube video can be useful. Say, if you're pointing out an editing mistake, being able to tell the creator exactly where to find it would certainly help. The process could be easier, though. Checking the timestamp manually and then inputting it correctly is a chore, and often the YouTube app doesn't recognize what I've done anyway. Thankfully, Google wants to make this process easier by adding a timestamp button for comments.

Much like the automatic chapters we covered yesterday, the timestamp button will only be rolling out to a small number of users for now. YouTube says that users in the test will see the new icon pop up as they're writing, and tapping it will insert the current time. It's currently in limited testing, but I hope this rolls out to more users soon because I'd certainly find it useful.

Source: Google Support