It does, yes. Protecting a Page that has children will effectively protect the parent Page and all of its child Pages as well. This makes it easy to protect a lot of content.
For example, whenever you create a Page in WordPress and set the 'parent' Page to one that is already protected via WooCommerce Restrictions, that will automatically protect the new child Page that you're creating; i.e., you don't need to go back and reconfigure any Restriction settings this way.
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