In the past decade or so, we've learned to equate the ability to collaborate with the need to be online. The advent of SaaS clearly marked the departure from a decentralized collaboration model to a heavily centralized one. While on the surface this is a very convenient delivery model, it simply doesn't fit a number of scenarios well.
As somebody once said, "you can't FTP to Mars", but we don't need to go as far. There are plenty of use cases here on Earth that are less than perfectly suited for this "online world". Lower power chips and sensors, vessel/offshore collaboration, disaster recovery, remote areas, sporadically reshaping groups—all these make use of central online services a challenge.