Number 1 blog photos and "candid" engagement photos are totally two different things. Blog photos you just stand there and get a photo of the outfit, engagement photos you really actually need to pose.
We one part were completely awkward and not prepared for this, and other part had a ton of fun and were so happy with the shots. It took about two hours in total (and a full day to get ready for the shots), where blog photos take about 30 minutes.
The whole thing was a good time and we are so happy we blocked off the day for the shots... and we caved and decided to get Christmas cards so this works great.