Not intending to denigrate this in any way because it is cool, but that video wasn't the board meeting (notwithstanding the title), that was the founder/CEO giving a recap of the board meeting.

Transparency can be a double-edged sword. For a healthy board in a healthy company this would be fine, for one which is already in difficulty it could make the situation worse as the frank conversation that could previously take place at board meetings would be driven underground.

Take for example a company that's at a critical point. Board needs to decide to a)cut costs by laying off some staff b)seek a buyer c)tough it out as some big clients are close to signing next quarter and will pull it through to profitability.

If the board conversation around this topic was public the big clients will probably pull out as they will doubt the supplier's long-term viability, key staff may leave rather than wait to see if they get cut and any buyer will be looking for a firesale.

So basically all the options (in this example) turn bad if the conversation is public.

Boards would never go for it because it would reveal how little work they actually do.