For myself I tend to be in one of two camps when it comes to effects - either an effect is spectacular, in the sense that it visually shows me something I have never imagined, or I am relatively happy with effects as symbols and signifiers.
I grew up enjoying programmes such as Box of Delights, where the special effects for a giant rat consisted of a man with some bits of fur glued to his face. There was no question of me "believing" that he was a grant rat but I was quite happy to accept him in that roll and emote accordingly.
And for me, however effects are achieved, they work in the same way. However an Orc looks, I don't "believe" what I'm seeing is an Orc because Orcs don't exist. Similarly if someone is swinging from webs across a city I know that that isn't real however the effects are acheived.
So for me the fine distinctions of Orcs as men in masks vs orcs as computer models are generally not at issue. The CGI goblins here look very similar to me to the actor-goblins of FOTR - though obviously I don't believe either are real goblins!
There is an exception to this which strikes me however. In this clip you can seen the goblins performing actions and being thrown around in ways which one could not see with an actor, although one presumably could with "real" goblins. So there is a strange little contradiction in the sense that such motions are flagged as "fake" in some sense because we know they aren't being faked by actors. Odd.
LR