For immortals, the most important thing is still the enlightenment of the Dao Heart.
Sometimes a single successful insight might be more useful than hundreds or even thousands of years in closed-door cultivation.
As Mo Shuang said, most immortals living in the Immortal City are trying to perceive their Dao from their daily lives. The Great Dao is formless; often, a moment of unintentional realization might break through a bottleneck that has confined one for countless years.
A few lines of poetry from Li Chen made many immortals on the top level suddenly feel enlightened, causing some unintentional memories to resurface in their minds.
This, too, is a form of enlightenment.
Although there are many native immortals in the Immortal Realm, it seems that the Immortal Realm places more emphasis on ascenders. Even some geniuses belonging to subordinate worlds of other Great Realms, once discovered by people from the Immortal Realm, would be forcibly brought over at any cost.
