If you ever wanted to see CGI done right vs it being done poorly, you don't have to look much further than Lord of the Rings and The Hobbit.
Lord of the Rings was full of CG, but it made extensive use of practical effects. Take the orcs for example; all the orcs have incredible makeup and propwork. They feel real. And I don't think any movie since has replicated that feeling, especially when it comes to sci fi or fantasy antagonists. The orcs are pretty scary in Lord of the Rings, and I fully believe it had to do with the practical effects that went into them.
The Hobbit meanwhile replaces all the insanely detailed orc makeup and props with giant CG models, and in doing so the effect they had in Lord of the Rings is gone. No longer are they legitimately frightening creatures, rather they're giant cartoon characters in a dumb fantasy movie. Just images superimposed on a screen. There's none of that groundedness that the orcs in the previous trilogy had, and as a result there's far less tension.
That's just one example, but I think that one illustrates the difference between the effort poured into the LotR trilogy versus the Hobbit trilogy (though to be fair, Jackson himself wasn't exactly given all the time he needed for The Hobbit unlike Lord of the Rings).
Lord of the Rings as a whole is fascinating, because sequences I believed were green screen and CG actually weren't, like the swamp in Two Towers. Turns out that was a flooded parking lot.