Let's create more stuff that only the rich can use.....
I have no idea how much it will be to use. I am rather sceptical of it being cheaper than high speed rail. Why would it be cheaper? Seems like a lot of r&d needed and probably more expensive infrastructure in order to save some air resistance.
But if it provides an alternative to air travel that is pretty much restricted to using ff for power density reasons. Faster and less reliance on ff sound like nice benefits but will costs escalate and kill this? If it gets that only the rich can afford it then it has no chance of getting the volume of usage needed to make it pay and not much will get built.
I am concerned that costs will soar, but if Elon Musk is convinced enough to start 'the boring company' then who knows? He is much more likely to have got his calculations correct than I am.