Back in 2018, we were running microservices in the ECS cluster by managing EC2 instances ourselves. It involved lots of toil work.

Without Fargate we had to maintain & monitor a pool of spot instances, choose the right size of instances, keep OS up-to-date, etc.

We want to ship features, not to manage servers. That's why as soon as AWS Fargate was announced, we migrated our microservices to this managed service. The only configuration you need is Docker image, RAM & CPU resources. The rest of the heavy lifting is taken care of by Fargate, which is wonderful.