Why is the phrase "including but not limited to" used in conference announcements?
This phrase is just standard boiler-plate verbiage.  

The title of a conference is generally too vague to define a community precisely, because different people might interpret such a short phrase in different ways.  Thus, when you are designing a call for papers, you generally try to give a bunch of examples as a way of giving a more concrete outline of the sort of community that you are trying to reach.  

But it's a highly inexact procedure, and the boundaries of communities are generally fuzzy in any case.  Thus, the "not limited to" phrase is included as a less informal way of saying, "If what we described kinda smells like your research, don't worry too much about whether it fits a bullet point, and just submit."