Sure, that's why I said convincing animations is a whole different thing.
You can have all the details in the world, models made up of millions of tris but it all falls apart if you move them wrongly.
For reference look at, well, almost any movie with cgi characters in it.
The motions are either so snappy that no weight is being conveyed at all or so uniform that it just looks artificial.
Then there's those terrible cliches that monsters always have to roar towards the camera and that stuff just has to move in a blur at some point which we'll probably never see the end of.
It's tiny immersion-breakers like this.
I have not yet seen anything cgi that looks 'real', no matter how 'realistic' it looks. If that made any sense.