One downside I see to this is the cost of the host for what will likely be a idling machine for a long time. Ultimately these services end up pinging some API or kickstarting a workflow, and the host itself isn't always super busy.

Looking at other services provided by AWS, Lambda[1] seems like you could easily schedule tasks out of the box, and not pay for the host/capacity unless your script is running. If all you are doing is pinging other services, it won't even be running that long.

[1] http://aws.amazon.com/lambda/

"Scheduled Tasks"

AWS Lambda functions can be triggered by external event timers, so functions can be run during regularly scheduled maintenance times or non-peak hours. For example, you can trigger an AWS Lambda function to perform nightly archive cleanups during non-busy hours.