Basically it's just a regular episode where the viewer doesn't really get anything more out of the 10 episodes of the Takara no Vidro series.

You get 23 additional minutes of the same story without really adding much. Time has passed (between 6 months to a year) but you can't really tell by yourself, as the show needs to do so with the "Takara-senpai returns from a long hiking trip" thing. The emotional investment of Taishin himself makes it feel like he went down the convenience store, not to another country.
Even the stalker turned BL fan fic writer felt cringey, despite me being actually curious about her POV in the teaser.

Personally, I think even those who really loved this show should just move on and find something else to enjoy, as this special seemed unnecessary, even counterproductive, as Taishin and Takara felt like roommates, not lovers.