Great! That’s how it should be. If you select the Multisite Configuration option the Connection settings (API key etc.), Webhook options, and Enable SSO options will be set for all your subsites off of the main site. It will also create the database table that’s used to associate posts with blog_ids.
If you don’t select the Multisite Configuration option, those settings can be made individually for each subsite. The best approach to take really depends on how many subsites you have. If you would like to use webhooks and you have 100 subsites, without selecting the Multisite Configuration option, you’d have to setup 100 webhooks. I don’t think that would be a great idea.
It’s quite late where I am. I’ll look at this in the morning and get back to you.