Its not a simple situation.
My bike came with Touratech head protectors. They look smart well up to the task. However the back end of the actual rocker cover still hit the road so I had a bent crash bars, badly scraped expensive farkle, a bent crash bar AND bent bolts that should never has see serious side loads.
Even worse, the M6 bolts, which hold the head protectors were bent Z shape. The Touratech covers had not yielded even slightly so serious crash loads were hammered directly into the cylinder head.
Ideally the bike needs head covers that will bend on impact so the cylinder head mounting points are not risking fracture. I'm not convinced about the X-Heads as polycarbonate is hard stuff. But the bolt holes can be elongated so the protectors can move inwards without bending the M6 mounting screws.
To be honest, a nylon crash pad bolted along the side of the rocker cover is all it needs. Enough to be sacrificial in a crash and cheap enough to not worry about the replacement costs.