The Google Home Hub, the one with the display, now supports speakable markup. When the Google Home Hub first launched it did not support speakable markup, like the Google Home without the display. But now it does and here is a video of the Google Home Hub showing off speakable markup working on this site.
Like I said, speakable markup simply was not supported when the Google Home Hub with the display first launched. Now it does.
I do have to say that I am more easily able to trigger speakable markup on the Google Home without the display than the one with the display. It might have to do with Google Home Hub trying harder to show video news clips over speakable markup. But I am not 100% sure about that, that is just my guess.
Forum discussion at Twitter.