At work, most of our deployment pipelines are something along the lines of "get some credentials, call a remote API and wait for it to say it's done". Occasionally, they also have "download this large binary from S3 and upload it somewhere else". Because these are in our CI, they are blocking steps that consume our builder resources.

We use Buildkite, so I changed their agent to run as lambda function, and used their eventbridge integration to trigger the lambdas. We saved about 15% of our CI costs by not using our 32 core build machines to call ecs wait-services, and freed up said machines to be able to run more often.