This is very true if you are one of the nationalities slated to get 72 hours. If passing through PEK in both directions on the way to the 3rd country and with wise scheduling and daily planning, you should be able to see the Great Wall and all of Beijing's major in-town sights, plus some relax or shopping time, in two passes through. It's a potential big savings for US citizens since their visa cost is much higher than others. But everybody on the 72-hour list can benefit by not having to go through the current application hassles and required supporting paperwork.

The only issue--non-Chinese-immigration--would be making sure the air ticket you plan to procure has a free (or nominal cost) stopover privilege, since of course this stint via PEK would move from connection to true stopover category. Hopefully this will be widely publicized quickly, so that boarding a flight with this PEK stopover on visa-less status won't be challenged by the airlines, with boarding denied....which is the main potential fly-in-ointment that I see. It took quite a while for the airlines to deal with the 24 hour TWOV idea, and some of them still don't "get it."