I see this as a good test for the rest of our society. If the NBA with all the money and expertise it has to set up ideal precautions and testing won't manage to get through a reduced season, then how can we expect the average business establishment to do it?
Of course, the major difference is most businesses can't afford to just close until next year, the NBA can, but, it is an interesting test. Also, NBA players are top level athletes and young, if they end up having an outbreak of covid-19, the hospitalization rates and long term effects should in theory be almost non-existent. This would but that theory to the test.
I would never recommend doing this just to test these things out, but since they are doing it on their own initiative, we may as well learn what we can from it.