I assume you mean the motion of sticking your arm straight out with your fingertips being used for something other than striking with your fingertips?
I can think of several grappling applications that can apply strikes, such as a leg sweep using the motion of an elbow strike or ridge-hand, or a palm strike to trap the attacker's fingers, but I'm completely blanking out on how a spearhand can otherwise be used.
I'm saying I must at least have an application in mind as a starting point. For example, an augmented block (what I mean by that is an outside block with one arm, and the other arm supporting the elbow). What is the application of that? I have a basis to start with the spearhand, but I don't even know what the purpose of augmenting the outside block is.
With no basis to start from, to me it's just an abstract motion I learn as part of the form.
Well, on the one hand, how do you know I haven't been trying to understand?
On the other hand, why is it not valuable to learn from my master? If I should just figure everything out for myself, I might as well stop training under a Master and just watch Bruce Lee movies and figure out how he did all his stuff.
As to the last bit, if someone is trying to figure out the application of the fall (i.e. what purpose might a fall serve in a fight) they might be down a different track of mind than what the question is (why it's important to know how to fall safely if you happen to fall).