basically this allows you to play multiplayer wiht your frineds if they are at your house and you have atleast 1 controller
To be fair, this isn't technically "local multiplayer". That term is generally held for LAN setups whereby you have either a network cable connecting your systems, or a switch connecting your computers together via network cables.
Yes, it is. Have a look at steam's list of "local multiplayer" games. There's no special name for multiplayer over LAN as there's no difference to a computer: network communication is network communication, regardless of whether the other computer is on the same router.
Are you sure that isn't to denote that the games have the capability to be set up in a LAN? Considering Steam also has a "multiplayer" category, it sounds more like the tags are a defining function that the game can be either in a LAN set up, or over the Internet. --- Post updated --- Hard to say. Maybe just refer to it as enabling multiseat mode, since that is what it is referred to in-game.
Nope, the steam tag is for spllitscreen. Local multiplayer does typically refer to same machines not network play. From a programmatic standpoint there is zero difference between LAN and internet play, there is a huge difference between splitscreen/hotseat/other single machine multiplayer and network play though.
Yes, I'm sure. Have a look at Co-Optimus: hovering over "Couch co-op" shows a pop-up explaining that that means "local co-op play".
Hard to say. Maybe just refer to it as enabling multiseat mode, since Yeah, I'm well aware of that. I've made the mistake of looking into networking code for Java and C++ before out of curiosity. Not quite comfortable with that level of complexity just yet. That being said, only now have I heard of "local multiplayer" referring to non-network setups. I am generally used to hearing non-network setups as "splitscreen", or in the case of BeamNG "multiseat".
But remember that if one day it becomes split screen (local, same computer), your fps may drop by half(because of two times the same meshes, textures)