Oh yeah, but there are other little details -- like, some people have their journals set up with certain modules that others don't, etc, that all affects the display. And we also like to make sure that we cover all kinds of preferences and accessibility needs; we might not notice from screenshots, for instance, that the entries are set up incorrectly for screenreaders or whatever.

Basically, the more human beings who poke at it before it gets added to the site, the more we're confident that things aren't going to be screwed up somehow!