I won't rehash this topic since chances are you already know a little about the arm-guards. Instead, I'll condense this down to basic arguments and questions:
|Figure 4. Bohemian Wrist-Guards|
A problem raised by Harry Folkens was that the stone wrist-guards are functionally overkill for the assumed job of string slap, whereas a simple piece of hardened leather would sufficiently protect the skin.
The decoration of Central European boar's tusks may suggest that a dominant bow used at this time (in Bohemia) was similar to the Meare Heath bow [here]. Reconstructions put it in the ball park of a 55-90 lb draw weight to the cheek for a 27-28 reach. So again, no need for a titanium wrist-guard.
As Turek outlines here and as previous authors have done, there is a reordering of functional requirements of its design, moving aspects such as appearance or significance higher in the design criteria than as a safety device. This is illustrated in the title "Symbolic Male Ornament"
Folkens makes this case as well by showing that 66% appear on the outside of the arm in burials, and this could be reinforced by the gold sheet bosses that appear in the tie-down holes of a few bracers. Turek they are more likely to have been worn in the interior of the arm but was simply rotated when not in use.
|Amesbury Archer (Jane Brayne)|
The facts do support the stone, or some stones, being attached to leather as some exhibit tannin etching. The stones show evidence of being worn, repaired, repaired again. The color of the stone as Turek mentions here, appears to have been very important and it would seem reasonable that the stone would be at least visible instead of a mere insert. And in the same way the bow is slung over the shoulder when not in use, the bracer may be rotated in a comfortable position as well.
But as we may or may not see in the upcoming paper by Ryan [here], shock injuries may have the real culprit, not skin irritation. In this case the stones could have been functional by adding dead weight to the forearm. The focus on the stone itself may be an artifact of the reality that it is only one component of a larger assembly that has disintegrated. So while we were at the earliest time correct to assume this item has something to do with being an archer bracer, we may be incorrect to assume that it is in fact an archery bracer.
Finally, the chronology and evolution of the stone-wrist guard is discussed. Here Turek suggests they originate in Central Europe then spread elsewhere and he gives evidence for this by their absence in early All Over Ornamented Bell Beaker graves. I'm assuming that the stone wrist-guard lacks a forerunner in a preceding culture and originates within the Beaker culture.
Interestingly, he sees the earliest stone wrist-guard as an elongated river pebble with perforations on either end. This simple and primitive design might be the best explanation for their origin. The link is at the top.