Meh, honestly I'm really skeptical of explanations that say things to the effect that often, people mistype as 8s or mistype as 5s or whatever. The way I understand 8, there's nothing all that mysterious about it. A smarter or more powerful 3 can kick an 8 lesser in those categories out of the water.
I think there's an actual difference in how these types all frame their attitudes towards their having needs to be fulfilled within the world. The gut types seem to rely least on a sense of ego separate from the world -- where an image type may wish expressly to build this up, so as to mark its significance, and a head type may build it up to figure out what the boundaries are separating it from the world/its ability to fulfill/threaten their needs.
So for example, 1 is the gut type closest to the image triad on the enneagram, and the idea is that, instead of establishing an image, the 1 perfects everything -- this implicitly obliterates the question of lacking worthiness in oneself, as one notices.
Similarly, 8s repress inhibition, which is a theme of the nearby 5/6/7 triad (where 7s straddle the lines -- gluttony is a mixture of inhibition/craving, where the focus is on not feeling denied, not on truly devouring).
They can be narcissistic or self-indulgent, and full of themselves for their power (if indeed they are powerful), but there isn't the same quest to establish their significance as with 3s. It's more a focus on getting one's way/having nothing stand in that way than a focus on one's worth/significance.