It's worth pointing out that higher-speed rail is technical jargon used to describe rail services that are not high speed, but aren't slow. Brightline is also apparently only planned to be higher-speed at some point, but currently has an operating speed of 130 km/h, slower than most definitions of higher-speed. There were regularly-scheduled services with comparable or faster speeds in the early 20th century in both Europe and the US; there were faster US services in the 1930 pulled by steam locomotives. Brightline is far slower than high-speed services elsewhere in the world today, going less than half the speed of many TGV services, for example.

With that said, as you point out, it's a new intercity service that is actually operational, popular, and being used today, which for the US is an enormously rare feat.