Cool to see young actors like Hudson and Curtis in such early roles

That was the old studio system at its best, and Universal was the last one to retain the practice of signing contract players, into the 60s. They hired young actors they thought were promising, gave them training in acting as well as in various arts that would be useful (horseback riding, fencing, etc.), cast them first in small roles, then slightly larger ones in lesser films, to give them experience and get them at ease in front of the camera, before gradually putting them in bigger and bigger parts and films until -- maybe -- they became stars.

Universal was also a good studio in that, unlike the bigger studios at the time, who were very guarded about loaning out their contract players, Universal saw the benefit of loaning its actors out to make major films for other studios. They figured that any success the actors had elsewhere would only redound to the benefit of the Universal itself, to which the actors were under contract. They'd become bigger stars at someone else's expense, and allow Universal to exploit that stardom for its own films. Plus, the studio got paid for the loan-out and could trade for the services of another studio's contract player. The mindset of most of the majors was that they didn't want to have their contract players making successful films for others, and certainly not becoming stars away from their home studios (as happened with actors such as Clark Gable, Robert Taylor, James Stewart, and many others).

By contrast, Universal was happy to loan Rock Hudson out for Giant, or Tony Curtis for Sweet Smell of Success and The Defiant Ones. From the studio's standpoint, it was a win-win for all concerned.