For me, the main reason for shooting 2,7K (I own P3A) is the ability to frame/ken burns/zoom in the post w/o losing quality (assuming the final video being 1080p).
Same for 4K+ - when I take TimeLapses with my Sony A6000, I allways do series of photos instead of video - the 6000x4000 frame gives me a lot more space/pixels for playing around in post, and raw format (ok, arw for sony) gives by long shot more info for color etc. corrections w/o running in quantization u.s. problems, associated with the jpeg and compressed video formats (I haven't any cam with raw video possibility)
If you do post-processing, then I totally get it. I do the same with my GoPro timelapses, shooting at 4K and then using pan/zoom to add some motion (final output at 1080p).