It cracked a critical path bottleneck for writing and debugging programs. In theory this could have been achieved as well with a direct access approach. In practice it could not. Direct access hems users in a static framework. Evolution is unfrequent and controlled by central and distant agents.
Creativity is out of the user's hand.
Time sharing, as it became popular, is a living organism in which any user, with various degrees of expertise, can create new objects, test them, and make them available to others, without administrative control and hassle. With the internet experience, this no longer need be substantiated.