There are multiple reason for filing a patent. I can speak to that as I have somewhere to the North of 50 patents over the years. The one big reason is to put a stake in the ground. That is do sufficient work to determine if a design or technology is feasible and makes sense then protect that IP with a patent. In reality 97% of all patents filed never pay for the cost of the R&D, preparation and filing cost. But it this sensor design turns out to be a good idea - Nikon owns it. Of my 50 plus patents only about 4 have ever been fully implemented. Don't get too excited about patents.
Yes it's clear from the description, but what is 'best'? - and their point is to be able to switch between 'speed' and 'dynamic range' depending on the shooting conditions.
Also they introduce three different operation modes of rolling shutter but I'm lost about the exact benefits of each mode.
I have patents where the corporation I worked for filed them not because they were so much interested in keeping someone else from using the idea as to get extra income when someone else wanted to make use of the idea.
Or, sometimes not extra income as such, but a swapping of patent licences so they could use someone else's bright idea.
One possible reason is to overcome a limitation of the global shutter operation mode, such as bit depth, so the photographer can choose a 12-bit, fast read electronic shutter mode, or a 14-bit mechanical shutter mode.