> With that background in mind it answers the obvious question
> of... why did the presenter show Unity through screenshots
> rather than a live demonstration of it?
Two reasons:
1) I really don't like giving live demos of software. I find it hard to keep them compelling for audiences because you spend a lot of time moving around in the software which results in dead time.
2) I wanted to switch to demo Unity during the questions because many of them would have been helped significantly with a demo. But, I could only get the projection system to recognize at 640x480. Which was fine for slides, but wouldn't have worked for demoing Unity.
Also, just as a shout out to JessyInk, the zoomable features of Jessy Ink are just so cool you can't not love using them! ( http://ubuntuone.com/p/fPv/#10_0 )
While I'd agree that Unity isn't 100% bug free yet (we've just hit feature freeze) I've been running it for a couple months on my personal computer and find it usable for day-to-day work.