I’ve set up the WP comments alongside the WP-Discourse plugin and I just noticed that it’s also possible to embed comments via javascript, as seen on Hacker, Hack Thyself
In scrolling through the JS embedded comments, I see a lot more features (number of replies, clickable dates, replied-to indicators, seemingly cleaner oneboxes, etc) than I see on the WP comments and I’m wondering, are there any hidden benefits to the WP comments coming from the WP-Discourse plugin itself?
AFAIK the main thing is that Wordpress comments are the “low code” solution for using Discourse for comments, so it’s usable by non-tech people on their wordpress instances.
The Embedding Discourse Comments via Javascript solution is more flexible but needs some tech chops to use.
Haha, I’m learning that right now as I try to customize the JS embeds 
I just noticed another benefit of WP over the JS embed: it seems that with WP Discourse comments, I can show comments even from a site that has login required, whereas with the JS embed that doesn’t seem possible.
It’s possible but the user must have a valid cookie to the Discourse site. This is usually used when both sites are under the same SSO login.
Ah, yes, with JS embedded comments, I’m able to see the comments on a private Discourse when I am logged in to the Discourse, however, not able to see them if I am not logged into the Discourse, a la:
Conversely, with WP Discourse comments, I’m able to see the replies from a private instance even if I am not logged into that private instance or not even a member of it.
I currently have it set up where my Discourse site is login required and yet I want public, non-Discourse users to see the comments on the WP site, so the WP method seems to work best for now.
If I want to allow only Discourse members to see them or I decide to remove the login required option, I’ll probably go with the JS embed because I like the added functionality it gives out of the box.
