I'm not from the US, and I think this is valid basically anywhere, although the lack of rail infrastructure in the states makes this perhaps particularly appealing.
The basic logic is two-fold:
First, it's much faster, cheaper, and less contentious to create new routes, and capacity can quickly be switched (even seasonally or in response to events) thanks to neither needing to pay for nor lay tracks.
Secondly, it shortens a lot of journeys. Even in countries with pretty extensive rail infrastructure it is common to combine two or more trips via "hub" cities in order to complete a journey. This adds time because you travel further and have to change trains and wait around. The difference could be particularly extreme given that only longer distance intercity trains tend to be high speed, and electric planes will eventually be faster even than high speed rail.
A similar change happened with long haul air travel: as twin engine planes have been able to fly further over water due to safety improvements, the traiditional hub model has lost out as many more point-to-point international routes were created.
While I think they might re-shape regional transport in some pretty important ways, electric planes won't replace high speed rail (and kerosene burning jets) on more popular routes, at least not for a while (and perhaps, debatably, never). Trains are incredibly efficient and hard to beat when you need to regularly move a lot of people, and electric aircraft, while they're about to become useful, are going to remain relatively small and range limited for quite a while.