Site Collection App Catalogs are great for special cases (like developing apps or site unique apps), but using them on scale would be a mess.

I got a question: Why should we use the Tenant App Catalog at all when we could enable a Site Collection App Catalog on every teamsite? So the suggestion here is to install SharePoint Framework Packages on many Site Collection App Catalogs, instead of the Tenant App Catalog. In that way those wouldn’t be visible for all users in the “Add an app” page.