It may or may not matter for various use cases, but the EC2 instances in the test use EBS and the AMIs are lazily loaded from S3 on boot. So it may be possible

It may or may not matter for various use cases, but the EC2 instances in the test use EBS and the AMIs are lazily loaded from S3 on boot. So it may be possible that the boot process touches few files and quickly gets to 'ready' state, but you may have crummy performance for a while in some cases. I haven't used GCP much, but maybe they load the image onto the node prior to launch, accounting for some of the launch time difference?