A future appointment at a physical location is usually an agreement between two or more humans. Humans generally don’t use UTC for future physical events, nor they use a time in a named time zone. What they use is a local time and location (often an address).
fauigerzigerk is saying that this, among with others, is the use case for what they are calling “local time,” what you are calling “nominal time,” what Postgres calls “timestamp without time zone,” and what the JS Temporal API calls “ PlainDateTime.”
In my experience engineers not understanding this key point, and believing that zoned time should be used for everything, is its own cause of issues and confusion.
What I'm explaining is that it's usually wrong to store a nominal (date)time that can't be resolved to an instant in time without assuming extra information that isn't captured.
If fauigerzigerk isn't arguing in favour of doing that, and I've misunderstood the prior discussion, then great. The point should be made anyway, because people doing that is by far the biggest cause of time-related software issues in my extensive experience.