I'm not sure I understand what you mean by extra.
This is what most villages look like gate wise these days. The PvP box is added onto the normal visitor gate. The point of having the visitor gate instead of a normal locked one is that you don't need a key to get in if you're walking from outside. The roundpole fence + visitor debuff acts like a locked door to everyone unless they have claim permissions. And even if you forget to close it, or someone runs past you when you open it, they're still stuck with visitor debuff and can't hurt your village. The pvp gate just takes advantage of this mechanic to treat it as a regular locked gate, but without any of the possible (although small) risks that come with those gates.
You can do airlocks without access to the inside of the village, but that means if you want to kill the person inside the airlock, you have to deal with anyone else they might have outside your walls. That's why you want some kind of safe way to enter the airlock, which I just combine with a normal village entrance here to make things convenient.