This is a ridiculous money grab...
I guess I have to open a ticket to understand why a user cannot access a page, even though the page has no restrictions, and they are in the same group as the rest of the company for whom it works for? Because I'm not buying premium licenses for the entire company for this.
The permission inspector is intended to help with large complicated setups spanning multiple products from a site level view. It's not for "basic troubleshooting" in any single application.
Basic troubleshooting of this problem is to get someone who can see the page to hover over the restriction padlock, and either clicking it to look at the page permission, or going up the page tree to see what the restriction is on the parent page (Confluence cascades ciew restrictions to child pages)
The insights tool won't help you with this, beyond telling you that the user has the right space access.