At this point in history, I don't find the insight very insightful. Maybe in Nietzsche's time it was; I don't think so, but I would need to know more about discourse at the time to be, ahem, objective about it.
The reason I don't find it insightful is that one aspect of it is trivial, and the other suggests an approach that is both dangerous and wrong.
The trivial part is Radical non-Twoism. Look around--do you see two? Actual two? No! You see two thumbs, two feet, two birds--you never see just two.
Therefore, there is no such thing as an objective perspective, and there is no such thing as two.
Well--quite obviously, two is an abstraction. So is an objective perspective. Okay, glad we cleared that up!
The dangerous part comes when you go beyond "oops, the objective view is an abstraction, not something that's physically instantiated as such" by appealing to viewpoint bias.
Firstly, if you add a bunch of bias together, you don't get truth. You get a bunch of biased perspectives. The bias might systematically all point in one way. Everyone might miss some essential aspect of what's going on. Theoretically, you can't have truth if you can't get past viewpoint bias. So this seems to suggest an end to truth.
Secondly, it completely papers over the different levels of agreement between different types of perspective. The whole point of objectivity is that there is a real reality there. Sometimes figuring out parts of it are easy; sometimes hard. The whole trick to gaining knowledge is figuring out how to get reliable perspectives--something that radical perspectivism suggests is impossible.
Except we do it all the time, and avoid walking into walls, and build iPhones, and pick many other fruits from the tree of objectivity.
So, meh. Not a very helpful framework. It's not like classical logic told you that your conclusions weren't dependent on your premises, though! "It-seems-to-me can contain hidden premises" is a valuable reminder.
But overall, kind of a yawn, and kind of pernicious, from a modern perspective.