Chad presented pan shots of formula cars travelling down a straight in broad daylight. You can do that with a camera phone. The question was if the viewfinder presents a slide show or the real action. It presents a slide show, which won't reflect changes in speed and/or direction of the subject soon enough for pan shots at slow shutter speed to be sharp. A Digital Rebel from 10 years ago would be better suited for this.
In the A7 II brochure, Sony has used no less than 7 photos of moving cars, of which 2 are pan shots over one and two pages. They are clearly out to prove a point here. They tried the same when they launched the A77, where they showed a burst of a gymnast taken straight on. Since that was a video, any experienced sports shooter would see that the video showed a slide show, but normal consumers don't necessarily notice things like that.
As for the buffer, the A7 needs 19 seconds to empty the buffer when shooting jpegs and 11 second when shooting RAW (SanDisk Extreme Pro (95Mb/sec) SDHC card). I don't know the reason for the big difference, but 19 seconds is an eternity when shooting sports. That's almost as long as my Fuji S3 took back in 2005. The Fuji had a "somewhat" smaller buffer though; 3 frames when shooting RAW with maximum DR
I don't know if the A7 II is faster.