Ranked in these QuestionsQuestion Ranking
Pro Supports multiple languages
Pro Supports multiple sources of events
Cloud Functions can be triggered from PubSub and from HTTP events, for example.
Pro Frictionless to create
There is an inline editor in Google Cloud for writing and submitting/deploying cloud functions, so while it is possible to store a Cloud function as code in a repository you can try and experiment without getting to that point.
Con Limited languages and dependencies
Only the set of languages explicitly supported by Cloud Functions can be used; for more flexibility, I would highly recommend Google's other serverless environment, namely Cloud Run.