I think the point was that Dropbox was not at the time viewed as "seamlessly moving data around". We see it in retrospect as revolutionary, but that was certainly not the view at the time since many of us had already seen online storage platforms come and go (xdrive, anyone?).
I will not comment on whether this calendar app is revolutionary, it might not be, but it's also possible it is something that will make an impact. There's lots of untapped potential in the calendar and event space, in my opinion.