You're missing the point. This is not about capturing the whole individuality. Both socionics and DCNH describe things that are both very pronounced/important in the individual and systematic. It's not just any typology. They are very relevant for understanding compatibility/communication. And because they are systematic phenomena they are easy to describe in a theory and use and also observe. That's the reason why DCNH and Socionics was discovered.
Just because you can't capture the individuality of all humans, doesn't mean that you shouldn't pick out some important patterns and describe them.