The two cars still link up quite a bit, though one will get an up-close-and-personal look at Finn avoiding blaster fire, while the other car escapes the blasts of an AT-AT.
As an example, Rise of the Resistance has two different paths depending on whether one sits in the first or second car in their respective unit.
The mobility a trackless ride offers is necessary for as in-depth as an experience as this ride is, and that will be evident once people get on and see just how much there is to take in!