I recently wrote about adding a convenience link to your posts and feed entry items so folks can comment/reply/discuss via email. Quickly and effortlessly.
An alternative to this is using the specs as intended. While not a convenience link, it still lets readers (like me!) know where to get in touch with you without opening up your website and hunting for an email.
Here’s the relevant portions for each of the spec:
Once configured, they show up like so on Miniflux (for example):