You can have your cake and eat it, too. Have a minimum of 1 instance "on", with the CPU in low-power mode until a request comes. This way, you get low cost in idle times without cold starts.

https://cloud.google.com/blog/products/serverless/cloud-run-...

But you get charged for that 1 instance running all the time which kind of defeats the whole point of it being serverless?

They say in the blog post those instances are charged a very reduced value when idle. IIRC something in the order of 20-30% of the original one.