That certainly works and is faster. But doesn't it turn UserData scripts into (part of) a provisioning management system? For instance in that example, you could have a machine die in the middle of the night, the autoscaling group replace it, and end up with a different version of node.js than the one you had before. Or the package server goes down and you can't bring up new instances at all.

I suppose you could bake everything into the AMI except your code, and hardcode the git sha into UserData to ensure your builds are reproducible. It just seems like it might get complex when coordinating lock-step code/dependency changes.