One of the criteria we are trying to push forward when considering proposals for pycon is whether somebody has presented at a local meetup or not.
A video of their presentations in pydelhi could be used for surfacing first time speakers.
Neither have I ever learned something entirely from video tutorials / recordings of conferences. However, there have been instances when video did help: eg comprehending the twisted framework would have been impossible without EuroPython's workshop.
A thought at the back of speaker's mind, that their presentation will be etched in time forever, will may be implore them to give their best?