With this setting you can publish the API Product and its included APIs in your Developer Portal. If you have multiple Developer Portals, this API Product is visible in the one that maps to the same organization.
If you have enabled guest access, the API Products that you want the guest to see must be public and published.
Inactive API Products are not visible in the Developer Portal.
Allow Subscription in Self-Service
This setting controls whether the API product is available for subscription directly through self-service in the Developer Portal. When disabled, the API product will be display in the Developer Portal but cannot be subscribed
General Visibility
When you create or discover an API or API Product, it is initially added to your organization. And is visible only to the members of your organization. You can add more organizations to this restricted view.
A public API Product is visible to all users of all organizations.
The general visibility also applies to the Developer Portal.