It’s not surprising that the first city pair would be a commonly traveled route with cheap flat land in between. Once that’s demonstrated to work, they can start trying it for cities where the need to purchase rights for the route will be more expensive, and on terrain where long straight segments are more challenging to construct.
I wonder how much traffic it will get.
This source says average, about 24,000 people drive between the two cities any given day, and there are about 30 commercial flights per day between the cities. That sounds like a decent amount of potential demand.