I think this would make sense on certain routes, like Beijing-Shanghai, where demand is so consistently high that someone will pay a premium for getting there quicker. Probably not practical for all current HSR routes.

I think these kinds of projects are really important to have because they're motivating. They show that real technological progress is being made and create optimism for the future. On a practical level, there's always a lot of new tech that falls out of this sort of stuff that's generally useful. For example, a lot of tech that was developed during the Apollo program ended up being used lots of different ways to improve lives of the people.