today, enabled parameter is used by spray to manage the order of deployment of sub-charts (e.g. all sub-charts enabled are set to false, and the sub-chart to be deployed has its enabled parameter set to true, and so on, to deploy all the sub-charts one by one).
it brings confusion especially because we may want to use enabled in a provided values.yaml to indicate we would like to deploy only a part of the umbrella chart (which is better than always use the --target or --exclude flag)