Reader mode also attempts to discard "unimportant" content – if you intentionally enter reader mode, it's fine to discard even things like the page navigation,

Reader mode also attempts to discard "unimportant" content – if you intentionally enter reader mode, it's fine to discard even things like the page navigation, but not so much for a browser's default mode. Plus sometimes it's too overeager and discards content that shouldn't actually be discarded (e.g. I'm hosting some radio show transcripts, and with my markup Firefox's reader mode discards the bit of text indicating who's actually speaking).