The compute Datomic CloudFormation templates (primary and query groups) create ASGs using launch configurations. Launch configurations do not support the full set of Auto Scaling group features. For example, you cannot create an Auto Scaling group that launches both Spot and On-Demand Instances or that specifies multiple instance types or multiple launch templates. In fact, AWS recommends creating ASGs using launch templates, not launch configurations.
We are interested in launch templates for its support for using Spot and On-Demand instances.
EDIT: As of 2021-10-20, launch templates will not receive any new EC2 ASG features.