Cloud functions emerged as a key primitive of the 12-Factor application model—treating computation as ephemeral logic with no memory of the past. Through their immutability, they became ephemeral: functions without identity, state, or persistence. Immutable things are often associated with eternality—but in finite systems, immutability means disposability. Without memory, the function cannot remain.
They offered scalability through statelessness, enabling horizontal distribution. But to achieve this, they externalized context, coordination, and observability.
The result: functions that are easy to run, but difficult to compose.