It’s well within the realm of possibility that the game features new content not seen in past games, or expanded features like in-depth lightsaber creation alongside a character customizer.
As such, that should be the goal of this trailer: to stand out among the other games there.
Showing these off would add more flavor to the game outside its natural LEGO tendencies, and it would do well to help the game stand out. It's well known that LEGO Star Wars: The Skywalker Saga’s hub are interactive, with events like a TIE Fighter attack being possible. Perhaps the most interesting locations could be the hubs. Since this is the first time The Last Jedi and Rise of Skywalker will appear in a game, it would make a lot of sense to show shots of various characters exploring new areas and locations. However, a gameplay trailer would be much preferable. From previous games, as well as the couple LEGO Star Wars: The Skywalker Saga trailers out there, fans may mostly know what to expect.