I don't think I did that with black rice.
Putting the yeast in from the packet and letting it sit for the first part is to allow an acclimation of sorts, since the moto is a balance of 'bugs' and yeast. Some of this is known to work on that balance. I wouldn't quite chalk it up to superstition on that one.
Crushed/cracked rice will interfere with koji growth
With proper rice, cracking grain is a signal something went wrong/was abused in the process. Maybe cracked rice won't soak the same amount of water/absorbs too much when steamed ...Most home brewers at 10 lbs may not see a difference, but regular batch sizes found in a kura may cause wrong water/rice/koji ratios.
If rice cracks when added to water/steamed, maybe milling got too hot which would have changed the proteins a bit in the rice, attributing off flavor? Dunno.
Rice breaks down during ferment due to enzymes attacking the structures of the rice. If the rice was crushed before hand, it would be analogous to a super fine crush of grains.. sure, it will mash, but good luck lautering. I believe it would impact the pressing later on. There is a balance between pressing out the sake and getting every sugar possible out of the grains. If you like nigori sake, go for it
I put my black rice sake into my own press, and due to press designs.. well I need to work on the press a bit.