FWIW, I implemented webmentions in my ghost blog (see one of the blog posts on https://blairmacintyre.me). It’s really an inefficient implementation, though, since I need to fetch the mentions each time someone views a page. My blog is pretty low traffic, so “it’s fine” but I’d prefer to have the mentions stored in ghost so I could just fetch new ones when someone visits the page (or have them pushed).
I like the idea of webmentions because I long ago abandoned commenting on my blog; I push all my ghost posts to my micro.blog (bmaci.me) which then get pushed all all my current social media accounts. I would like the discussion to occur in those places, not on the blog, and this allows me to aggregate some indication of activity. So I tend to agree with @MayanMisfit, but I understand that others might like comments, and I don’t see them as incompatible (even if I have comments, I’d like to have and show some record of external mentions).