In some instances AWS uses different service names in events and boto3 client instantiation (ie "elasticloadbalancer" and "elb"), which prevents automatic client instantiation. By allowing users to optionally pass in a service name we could allow them an easier mechanism to work around this issue.
Also if there arise instances where users need multiple boto3 clients for different services, this would give them a mechanism for creating those clients.
In some instances AWS uses different service names in events and boto3 client instantiation (ie "elasticloadbalancer" and "elb"), which prevents automatic client instantiation. By allowing users to optionally pass in a service name we could allow them an easier mechanism to work around this issue.
Also if there arise instances where users need multiple boto3 clients for different services, this would give them a mechanism for creating those clients.