For the first time I did it, the time itself doesn’t appear in the notification, so I was hesitant/unsure that it was set properly. Then, I wondered what time zone the system would use for the topic timer. But, it all worked out.
In general, I think the time zone feature would be magic for doing announcements/posts in our global community. If I want to get something out for our team in Oxford at the start of their workday, knowing that I have it configured for 8am BST adds clarity and confidence to the workflow.