My view having tested it extensively is that it's a mixture of a shadows bug and how shadows would actually look because once again we've become so used to being shown out hardline shadows that are not accurate vs soft shadows that cascade depending on the solid object distance to the surface the shadow is being projected onto from the Sun.
Here are two examples, the first is static screenshots which is what most places seem to be showing to demonstrate "RUBBISH RT SHADOWS!!!!!":
IMGSli comparison >>>
https://imgsli.com/MzU4NDY0
Now in motion having RT shadows off shows the actual lack of quality of the shadow as it's too hard edged and contains stair stepping and obvious alias problems even though the other shadow settings are maxed out and set to softest:
(might still be processing, give it an hour)
The problem both video and stills show in the above examples is that depending on the object casting the shadow, some shadow edges are muffled into the overall "shadow", like the palm tree on the wall section the individual leaf cutouts are only visible with RT shadows off, now would these cutouts be visible in real life in the same situation? I didn't turn the camera around to see the distance of the palm tree b but it could be argued that it would not and you’d just see a general shadow cast on the wall as the distance from the wall to the tree vs The Sun is such that this sort of detail isn't optically possible?
The Ferris wheel however is much closer to the ground than the palm tree is to the wall and is a much larger structure so you would expect to see some soft shadow outlines of each spoke, which you actually do on the boardwalk decking for the most part but it's more obvious with RT Shadows off, though detail is better retained with RT Shadows on Ultra.
As I say, I think it is a mix of a bug with RT shadows, as some stuff should clearly still retain hard edge detail in the shadow being cast, meanwhile other stuff would naturally be soft in real life. All down to the object and distance between surface and the Sun.