If parameter "host_registration_insights" is set to true:

Host is enrolled to Insights via insights-client during registration.
Host is included in the Satellite Inventory Plugin report.
If parameter "host_registration_insights" is set to false:

Host is not enrolled to Insights via insights-client during registration.
Host is omitted from the Satellite Inventory Plugin report.
Users who wish to use Satellite Inventory Plugin for Subscription Service purposes but do not want to enroll their systems to Insights will need to consider alternative solutions such as:

Register hosts with “Setup Insights” set to “No" and flip "host_registration_insights" back to “true” on the host level after registration.
Edit the insights-client part of the Global Registration template.
Those users would benefit from having a separate parameter for each, i.e.:

"host_registration_insights" to determine if a host should be enrolled to Insights.
"host_registration_inventory_plugin" to determine if a host should be part of the report.