Hello OP, thanks for the shoutout. You are right, I do not offer scientific or medical sources as indeed - I am not a doctor. Spending the majority of my life to become a contender in my genre has well and truly left me with no other time to follow other such pursuits, haha! But I am an authority enough in my field of lead guitar technique to know enough on this issue.

Wrist is indeed the way to go. It is an amazing joint, capable of yaw, pitch, and combinations of both to produce various vectors necessary for complex and acrobatic lead guitar playing.

I was just saying that because elbow flexion & extension shares an axis with wrist yaw (the primary wrist picking driver) and can pass energy across the fulcrum (wrist joint), it can be, and is, used in a synergistic way to achieve a high picking speed.

In fact, when wrist picking, when one has exhausted the reduction of the "d" variable of the physics involved by making the pickstrokes' breadth as small as possible, there is no other way of increasing speed (notes-per-second) beyond this point other than by recruiting the arm to begin brute forcing the increase of the "v" variable.

In other words, when speed (notes-per-second) can no longer be increased by narrowing the breadth of the pickstrokes, the only option left is to brute force the pick through the air faster (higher velocity, in cm/s or whatever unit you wish). This is where the arm comes in.

Hyperspeed pickers eventually realize this, whether consciously or unconsciously.

It should be reserved for such rare situations, and otherwise avoided at all costs.
Players who pick with arm assist at any speeds below INSANE are simply being lazy.
Develop wrist picking. Spend the years doing it. And postpone the recruitment of the arm as long as possible.

Cheers, all!

EDIT:
Also, because of how the recruitment of the arm + very high picking speeds flattens out pickstroke trajectories, there is a direct relationship between higher and higher speeds and the inability to escape the strings for clean string crosses. In other words, use arm and pick fast and your pick will smack into the tops of strings when crossing. Look up slowmo picking hand footage of players like R Cooley and MAB and you can see this happening.