Lore reason for P having a prosthetic arm

[Lynfinity]

It's entirely possible that I'm just stupid and overlooked an obvious and right-in-your-face explanation, but what exactly is the reason Geppetto equipped P with a prosthetic arm?

We know why he created P in general - to store Carlo's "life essence" until he was ready to revive him. The arm, though, is still a mystery to me.

[Mako]

I guess its just easier to mod and integrate weapons this way. Its not a prosthetic btw. P's entire body is robotic and is only covered by (probably artificial) flesh for blending in, like Terminator T600/800. You can see a similar design in a couple of bosses.

[Zogtar]

Idk man, it felt like a "member sekiro" gadget to me.