It's a little "memorial" for a girl who has left us.
Sachi's face was fixed by the cruel fate when she's still teenage. I don't care what SAO was up to, I just know that she's no more than one of many innocent people who were dragged in this mad survival game and killed. No matter her death may mean someting or not, I think the very thing we can and should do is to keep her in our memories.
By the way, we can also learn a little about why Asuna becomes "the first mistress" in the story of SAO: She can even show toleration and kindness to her greatest rival so that most people can hardly criticize her personality.
Next time, by a doujin which will be released in C86, I would like to hold another "memorial" for another poor girl in SAO.
Seems like this isn't solely based off the anime/novel itself, but from the SAO: Hollow Fragment PSV game. There's a mention of Ark Sophia (the hub town in-game), while Kirito and Asuna are traversing the Hollow Area. And true to the game, Sachi (or what's left of her anyway) can be recruited as a partner in that aforementioned area.
Sure, there are unlockable "bed scenes" with all of the girls... though, I don't think Sachi can be romanced to that degree in-game. At least the game patch for it isn't implemented yet...?