Anyone wanting to use Vue or React normally builds two things: the front end, and an interface through which it gets its data. That interface is real work, even though nobody except your own front end uses it.
Inertia leaves it out. The application answers neither with finished HTML nor with a general interface, but hands exactly the data this one page needs straight to a component in the front end. Routing and permissions stay where they belong, which is in Laravel.
When the route fits
Inertia makes sense when there is experience with Vue or React on the team anyway and the interface is getting demanding, but there is no second consumer of the data.
As soon as a mobile app or another system needs the same data, the picture shifts. Then the interface appears regardless, and it should be cut from the start so that several consumers can work with it. What matters there is under API and backend development.