Is the purpose of scaffolding just for learning? When I was just starting, I built a twitter clone using a scaffold in about 5 minutes and ... I learned nothing. I then spent a week coding it by hand and learned rails.
I don't think I'd ever use a scaffold in a production app though. For that, I'd ether find an appropriate gem or write the code myself.
Yes, I think scaffolding is primarily a helpful learning tool... especially for learning how to wire/connect different gems, javascript libraries, etc., together into a working example. Often no single gem will provide everything you need.
But you have to take the time to learn from the example, or I agree you'll get nothing out of it.
I don't think I'd ever use a scaffold in a production app though. For that, I'd ether find an appropriate gem or write the code myself.