Probably Dessa started those demo conversations with some context, so maybe it could receive documents and speak about them. If those were random conversations started with no context, the people at Block probably recorded a lot of uninteresting chat and cherry picked the few good ones.
What prevents them from adding tool integration?
How would those tool calls work? Would it say what it wants and another model/system act on that and 'read aloud' the document to it?
I guess that's somewhat how we do it, so maybe it would work.