It is my understanding that the Zone system was adapted by photographers to deal with the limitations of film+paper combinations in darkroom days. The objective was to control the contrast of the scene (given\fixed at the time of exposure) via adjusting the contrast of film\negative (variable: exposure time + development) to match it to the contrast of photo paper (fixed). In other words, by expanding or contracting the contrast of the negative, the objective was to "fit" the contrast of the scene into the predefined contrast of the paper and have the print looking in a certain way, "pre visualized" by the photographer.
From my experience, the "hybrid" method of image production (images captured on film but final presentation is done with application of digital processing) has much fewer restrictions and limitations compared to traditional darkroom method. In particular, modern scanners are capable of extraction details from film with densities exceeding 4.0 and many are capable of seeing into up to 5.0. From my recollection, max densities of B&W negatives rarely approach 2.0. Hence, scanners or digital cameras do not have issues with extracting details from most dense areas of B&W negatives (and color negatives for that matter too) no matter how bright the highlights of the scene were. As such, all the contrast manipulation can, and in most cases, should be done on digital data due to offered by it convenience and flexibility.
In my opinion, with a hybrid method of image production, the benefits of the Zone system are not worth the efforts.
With a hybrid method there are 2 things that really matter :
* Proper exposure - to prevent loss of shadow details (expose for the shadows and let the highlights fall where they may)
* Proper development - to prevent detail loss due to under or over development. "Normal" development usually takes care of both extremes.
The hardcore darkroom printers may argue that it is important to control the highlight development via "+" and "-" development, but in my opinion, with hybrid method there is no obvious proof of benefits from doing so.