They can fight Godzilla or a T-Rex. They live in hidden jungle cities filled with ancient treasure. They are worshipped as gods by native heathens. They shoot Kryptonite beams from their eyes.
Truly, art and literature would be lesser in every way but for the Giant Ape.
The best of the Giant Apes are frightening and destructive forces of nature, but also, they're a little sad on the inside. They tear shit apart with total abandon, bite people's heads off and trample native villages, but they maybe feel conflicted about it. On the one hand, it's delicious and invigorating to slay and destroy all that you survey. On the other hand, the horrified screams of the children sting a little. Giant apes usually are forced into lives of mindless rampage by the Hubris Of Man. The lesson is that we should not meddle with nature, or tamper with things beyond or reach. It takes a Giant Ape to remind us thus.
There is a primal something-or-other going on with regards to the appeal of the Giant Ape. Maybe our fascination stems from an ancient racial memory of hiding from them in the jungles. A memory that lives in the same part of the brain that makes us horny when we see just a little bit of girly ass-crack slipping out of a pair of jeans, and drives women to want kids so bad that's all they talk about all the time. Seriously, what's with that? Take a girl that's all independent and cool and doesn't care about having kids, crank the clock up to thirty, and suddenly it's all "baby" this and "baby" that and "I forgot to take my pill". The next thing you know, you're ebaying all your old comics to buy one of those enormous all-terrain strollers.
Anyway, anyone who says that the original KING KONG isn't the greatest movie ever made is a filthy liar.