I think 1000 km/h travel would bring HUGE benefits.
State-of-the-art high-speed trains at 350 km/h tend to waste less time than planes for distances shorter than about 1000 km if you include the time it takes to get to the airport, check-in, go through security, and all that nonsense. Beyond 1000 km journeys, planes tend to be more time-saving.
1000 km/h is about the cruising speed of an aircraft so if it were possible to achieve that with a train, it would no longer make sense to take planes for the same journey -- which would be HUGE plus for comfort for, say, trips between Europe and Asia. Imagine for a 10-hour journey that you could walk around freely, enjoy massive amounts of legroom, enjoy the views of Siberia, sleep in peace and quiet, dine at a dining table, and not have to be strapped into a seat all the time. For high-volume routes it is also likely to be lower-carbon in the long run than air travel, and at the very least, can be powered on something more sustainable and less polluting than jet fuel. The bulk of your environmental impact would come from laying the track itself, so it would have to be a route of extremely high tourism or business importance, e.g. Shenzhen-Shanghai-Beijing-Moscow-Warsaw-Frankfurt-Paris-London or some such. Or Los Angeles to New York.
As opposed to the countless survivors of most plane crashes.
Not to mention the one critical advantage of the train, run out of fuel or some breakdown, you just stop in the middle of nowhere, on a plane, it's likely a different ending unless flying near Hudson river with an amazing pilot.
High speed trains don't derail that often if built well. Modern high speed rail systems have better safety records than planes.
China's high speed rail system has had 1 accident with 40 deaths out of several billion passenger kilometers of trips, and that was involving a slower, older technology. The latest, fastest trains in China have not had any accidents to date.
Japan's Shinkansen has had 2 derailments in half a century of operation, one due to an earthquake and one due to inclement weather. Both incidents had zero injuries.
The European systems have had notably higher accident rates but still surpass the safety records of planes.
State-of-the-art high-speed trains at 350 km/h tend to waste less time than planes for distances shorter than about 1000 km if you include the time it takes to get to the airport, check-in, go through security, and all that nonsense. Beyond 1000 km journeys, planes tend to be more time-saving.
1000 km/h is about the cruising speed of an aircraft so if it were possible to achieve that with a train, it would no longer make sense to take planes for the same journey -- which would be HUGE plus for comfort for, say, trips between Europe and Asia. Imagine for a 10-hour journey that you could walk around freely, enjoy massive amounts of legroom, enjoy the views of Siberia, sleep in peace and quiet, dine at a dining table, and not have to be strapped into a seat all the time. For high-volume routes it is also likely to be lower-carbon in the long run than air travel, and at the very least, can be powered on something more sustainable and less polluting than jet fuel. The bulk of your environmental impact would come from laying the track itself, so it would have to be a route of extremely high tourism or business importance, e.g. Shenzhen-Shanghai-Beijing-Moscow-Warsaw-Frankfurt-Paris-London or some such. Or Los Angeles to New York.