I think in a kura that is continuously producing sake that the issues related to requirements of repeated rice steaming is irrelevant as long as a proportional amounts of sake batches is started at proper time intervals.
The issue is more relevant to smaller scale kuras/home brewers, where a daily supply of steamed rice is not a necessity. In these cases one day can be reserved for rice steaming. This reduces the workload by reducing the amount of times that the brewer must prepare/clean-up steaming equipment.
One issue is related to temperature control during sake brewing and the moisture content of the steamed rice. In a video
on sake brewing,before rice is added to the fermenter, the brewers reduce the temperature/moisture content of sake rice after steaming. This process is carried out for a varied timeperiod corresponding to the stage of fermentation. However, this is a video on producing the highest grade sake at very traditional methods, and there may be more modern methods for producing similar sake. Either way, I am sure most of us would be pleased with some sake that is just of half the quality of the sake produced in the video.