I didn't really know there's any difference (although if I'm being very informal I make add a piece of punctuation that seems a little more expressive or fun, sort of..). For the most part, the only thing I know is "regular grammar" and punctuation.
guilty! I'm a sappy romantic.. "at this point in time" sounds like it belongs in romantic novels. Sometimes, I use it to make a point. Grammatically incorrect.. but it's quite effective to emphasize time.