I think micropayments may not be necessary for this type of business model. For crypto implementations a better way to do it might be to allow people to purchase "credits" in advance which can be exchanged for watching a certain number of games. Like say they might offer 5 games for $4. That way a person could purchase in advance which would cut down on the wait time and network fees for btc.
I'm not certain anyone is watching NBA these days. It seems like there are always only 2-3 teams that are doing well. Every other team has something like a 20-40 record. I would guess NBA audience and tv ratings are declining which is why the NBA is reaching out and attempting to find new ways to monetize their games and draw in viewers.