According to Netflix's production guide for the S1H, you have to shoot in at least 4K using the V-Log color space with 4:2:2 10-bit All-I (400 Mbps) encoding. Crucially, Netflix requires a pixel-for-pixel sensor readout with no line-skipping. The S1H can handle that either by cropping to a Super 35 portion of the sensor (approximately APS-C) or using the full width of the sensor. The latter makes the S1H the cheapest option, by far, for a full-frame camera -- a good option for cinematographers who want shallow depth of field.
The S1H is approved for anamorphic productions in academy 4:3 capture in 4K, or to pick up the odd B-camera shot using 6K large format for shallower depth of field (3:2, 5,888 x 3,312). You can also shoot slow-mo at 60 FPS 4K using a cropped, Super 35 sensor size. Other settings on the camera like in-body stabilization and e-stabilization can be used with some limitations imposed (no panning with the boost I.S. mode). The S1H has a number of other features that likely helped greatly with approval, especially its time code jamming capability.
The S1H isn't a cheap camera at $4,000 for the body, but it's by far the cheapest full-frame Netflix approved camera. Mind you, the body price is just one part of that equation -- the lens alone on the front of the camera above retails for $10,000.
Update 10/24/2019 2:22 PM EST: The post has been updated to point out that 6K anamorphic capture can only be used for B-camera, rather than main camera shooting, due to the lack of an I-frame codec in that format.