I think those big screens are also there to give the poor devs a sense of accomplishment too. If you look at their blogs, they pretty much have at least one screen of Messe-Sanoh or Tora No Ana with their game being showcased (happened with Cloudphobia, Diadra Empty, PriZhm, Ether Vapor and many many others).
Plus it would be cool to see the reactions of people not used to bullet hell or shooters in general... UFO Extra being showcased might have caused a "heh, I think I'll stick to the doujinshi and arranged music" reaction :V (obviously, the glorious "stubbornness spirit" might force some people to get the game and see things for themselves)
If I'm not wrong, Himeyashop has a blog where they portray news now and then as well as a Comiket report. It used to be in english although that one was shutdown?
Ok, question about that Touhou fan fighting game (the one in 2D with the cute sprites). Question for the people: what do you think of this one?
Link:
http://www.daiojyo.com/touhouhaou.html