The Archer is less devastating (even though I would not be surprised if it was as valuable as a Queen), because it can only rifle capture from nearby, so it cannot do it from cover.
BTW, your definition of 'guarding' is a bit murky. What if white has Rook at a4 and Friend at h4, while black has a Rook at e4? This makes a4 what the Chu-Shogi rules would call a 'hidden protector', as after black's Rxh4, it would be able to recapture that Rook. So can the Friend borrow the moves from that Rook? I guess that is not what you want, but your definition is not clear about that. The reverse case would occur if there was a Cannon on a4. After Rxh4 the Cannon now cannot recapture that Rook.
The point is that the possibility to recapture is a dynamic thing, which depends on how you captured. It would probably be better to use a 'static' definition, like "when it would be able to capture the Friend if that had been an enemy pawn".
The Archer is less devastating (even though I would not be surprised if it was as valuable as a Queen), because it can only rifle capture from nearby, so it cannot do it from cover.
BTW, your definition of 'guarding' is a bit murky. What if white has Rook at a4 and Friend at h4, while black has a Rook at e4? This makes a4 what the Chu-Shogi rules would call a 'hidden protector', as after black's Rxh4, it would be able to recapture that Rook. So can the Friend borrow the moves from that Rook? I guess that is not what you want, but your definition is not clear about that. The reverse case would occur if there was a Cannon on a4. After Rxh4 the Cannon now cannot recapture that Rook.
The point is that the possibility to recapture is a dynamic thing, which depends on how you captured. It would probably be better to use a 'static' definition, like "when it would be able to capture the Friend if that had been an enemy pawn".