for an application layer cost effective solution which is best: Fargate or EC2 Auto Scaling group?

there is a application layer with OLTP db layer. The architecture needs to be available at all times and WILL experience periods of inactivity. What is more cost effective : 

o FARGATE + Aurora Serverless or 

o EC2 behind an Auto Scaling group + My SQL

I assume it is Fargate due to better idle time handling according to this article:

https://aws.amazon.com/blogs/containers/theoretical-cost-optimization-by-amazon-ecs-launch-type-fargate-vs-ec2/

Is this correct?