Very interesting. When I think about it, some of the most compelling speakers I know, including highly intelligent people, drop a "word bomb" somewhere in their main points now and again.

Aside from giving those statements a bit of emphasis, it apparently makes them a bit more "sticky" in memory.

I think the lack of those statements and then the occasional 'drop' is what makes it memorable. If they used it on every other word - wouldn't have the same effect... certainly an interesting observation... perhaps it's memorable because it's unexpected.