In my experience, it shows the total number of page views since page creation. Though, the method to calculate page views is not known to me, so it could be different. Its not stored in any hidden list or something, but in some data store for which we dont have any API yet.
The Social Bar will appear on all modern SharePoint Online pages with
the exception of the home page of a site. It will give your users the
ability to like a page, see the number of views, likes, and comments
on a page, and see the people who have liked a page. This visibility
will be available to anyone that has been granted access to view the
This is what appeared in the message center.
To disable it at tenant level, you can use below PS command:
Set-SPOTenant -SocialBarOnSitePagesDisabled $true
or using PnP
Set-PnPTenant -SocialBarOnSitePagesDisabled $false
To disable it at site collection level, you can use below PS command:
Set-SPOSite -Identity <site-coll-url> -SocialBarOnSitePagesDisabled $true
You need to ensure that your SPO PowerShell is the latest version or atleast a version after Feb 2018.
Also, looks like it can't be disabled on modern team sites because of a bug on the Microsoft end of things. Works fine on Communication sites.
So, to answer your question:
It will be visible to all users who have read rights on the page. If you want to hide it for certain group, use application customizer (not recommended though because Microsoft controls the rendering and if the DOM structure changes, you will have to modify the code, better disable it for all users or show it to all users IMHO)