Japan and afaik also china are building long distance maglev lines at the moment. We will see if there are any issues that regular hsr wouldn't have. It's certainly expensive to build, but high speed connection between major cities can be worth it. Technology that can go at almost 2/3 the speed of planes but is able to run entirely on electricity isn't necessarily just some gimmick, there is an actual use case for it. 300 km/h is fast, but 500 is a lot faster. Of course just like with existing HSR, building routes that support these high speeds is a challenge (and part of why japans line under construction is so much faster than the existing shinkansen is that it just cuts straight through the mountains, which is of course expensive).

The planned line is supposedt to be even faster than flying (45m vs 1h) overall, probably due to the overhead of taxiing. And that's without considering security.