Does this add-on allow for Glossary terms to appear in PeepSo posts on the site?

Yes, or at least this is optional. Within the Add-On settings you can toggle whether or not to display tooltips in PeepSo Posts.

You may wish the PeepSo posts to be a cleaner tooltip free area of the site or you may want it to behave as the rest displaying tooltips for key content.

To learn more about displaying tooltips in PeepSo see this Help article.