For landscape, apart from convenience (if you're too lazy/find it too bothersome to take the trouble) why use AF at all
Subject isn't moving, won't run away, so plenty of time to select and focus on the area in the picture you absolutely want in focus (maybe even making some adjustments for a as big as possible 'in focus' area by calculating the best setting based on the hyperfocal distance)
And if you do want to use AF, yes, AF-S definitely is the best choice, witH AF-C focus will jump/change whenever the selected AF point/the camera is moved
For general photography though, I prefer AF-C with a single manually (by myself) selected AF point using Dynamic AF with 51 AF fields, no 3D, auto area or group AF, with priority on Release rather then 'In focus' (I don't have a D750, but as I eg recently found out helping a D750 shooter, fortunately Nikon is quite consistent with the AF options for the several bodies it offers, like in my case D3, D800, DF, D7100 allowing a high degree of compatibility)
I choose this relative simple setting (ant to ignore the supposedly more advanced ones) since I prefer to be the one who decides what the camera focuses, at least initially, on
I shoot a fair bit of catwalk and (non static) on location fashion, and in the past have also shot quite a bit of sports/surf
and admit that with a moving subject it isn't always possible to follow the subject with the selected AF point
But being a Nikon AF user since the F801, I over the years have learned to trust the steady improvements they made in AF tracking and dynamic AF (not that that was perfect from the beginning, I eg found out the hard way the multi point - just 5
- Dynamic AF on the F100 at that time was a disaster)
Another consideration is that, as I shoot non static/moving subjects (most of the time)t, with AF settings like 3D and auto area, the camera after I push the release button based on it in camera logarithms makes an analysis of the image and independently decides what to focus on
Apart from basically putting me on the sideline during that process, it also creates a small delay between me pushing the release button and the camera having decided what to focus on.
When shooting sports, catwalk or a moving model, that lag may just be the difference between a nice and an (perhaps) exceptional picture, and that's a risk I'm not willing to take
Of course using a single AF point in AF-C means that if the AF point is moved only just a little bit from the area selected to be in focus, the focus changes, and not always for the better (although I have learned that Dynamic AF and focus tracking can do much positive in that regard with a moving subject
But IMO that's a risk/consequence of the setting chosen
It in the end IMO boils down to which you consider important/is important for the picture to be taken : absolutely sharpness even if that means perhaps missing the 'moment' (not a biggie shooting landscapes or close up portraits), or catching the moment, at the risk of perhaps not getting a perfect 'in focus' shot (a for me major consideration when shooting catwalk or sports)
