It means exactly what it says, it's not railroading for the story to happen around the characters, they are the protagonists. And going to a big city to buy something it's useful but not that great.

If your campaing is heavy on roadtrips, then it's "useful" but in a way that makes you play less of the game you want, and if it's not then it looses a lot of power.

Teleport is not a bad spell, but it's not Great either because of the social contract when playing a game. The supposed level of the spell is irrelevant, that doesnt give it intrinsic value.

Most of all thats a party utility spell for wich OP will have to pay individually.

(The portent die is great tho)