You're missing the point, you're still together in the same world and at the same time you're given the freedom to go your own way, play your own way. You can play an evil character or whatever while your buddy play how she wants. It's not a hard concept to grasp.
Im affraid you are missing the point pal. O_o
I mean, you are corect ... this is indeed how it works, but this topic was talking about party limitation to 4 members, that dont have much to do with people being together, or separate ...
The "point" here was sugestion, to allow people to create their own parties in multiplayer, or take the unused companions if you wish.
Meaning yes, play exactly the way you described ... but while controling more, than just your character.
Truth be told, when you play as 4 PC ...
Companions spend whole game just lolygaging around the bonfire in your camp, and what is even funnier, you cant even complete some of their quest ... like take Wyll with you to confront Spike.
And it all just problem of limitation of "four member party".
