Yup, if it’s foreseeable for a rider to use lower cadence due to course conditions and bike setup, it’s very wise to include that type of cadence in training. It all goes to idea of maintaining a wide functional cadence range. There are a number of reasons we may be forced to the fringe or outside of our comfortable cadence range. So, including this seems quite relevant and even important in my eyes.
I started a guide on the low cadence work for those that want to look at that option.