If you mean, Site will crawl more often if you use tags, then there are also many crawler factors which Google using it. And if Googlebot crawl and index content regularly by using categories links and sitemap file, then why need to use tags?
Discourse is devloped by jeff, who is also one of co-founder of Stackoverflow and SE sites, where he used tags, so user can answer specific question on specific tag. And hence jeff inherits many functionality like SE on discourse as well.
Tags on wordpress have special purpose, to make searies of content, and by using categories, you can also do the same, hence I say OP to check other website who’re in same niche, so he can get some ideas. But if OP still want to use tags, then I recommended to use noindex meta tag on such a low quality pages.