Pages don’t appear in any listing automatically, pages are intended to be separate entities that are linked to directly as they form the static structure of your site like the about page or customised landing pages.
If you are expecting your page content to appear in a tag listing then it sounds like you should be creating them as posts rather than pages.
An example use-case for tagging pages would be with a more complex site architecture where you build up custom navigation using the {{get}} helper in your theme.
Thanks, I use pages as you suggest, for structure, but was lured by the tag option! Wondering why the tag option is there for pages if it is only for rare use case theme development?
Those use-cases aren’t so rare, tagging pages (especially with private tags) is incredibly useful for many reasons other than more complex navigation.
One example is using a different template based on a page’s private tags so certain pages have a different layout, that would let you tag some pages with #help for example so that your site’s help documentation has a different layout to your typical landing page or post content, or to have a #no-ads tag to turn off some automatic ad insertion for certain pages.