I decorate homes in game, I rarely loot dead people because it feels wrong and I use lots of survival mods, but I still end up super rich without stealing really anything. For me, thousands of caps is already getting into the silly numbers for the fallout world, let alone tens of thousands. But still, I keep all the caps because they are weightless and I keep thinking "maybe I will need this later"
I guess I am kinda a "powergamer" in that I like to consider the limitations in my game world. When going max-min I don't try to make the most powerful character ever, but I do try to understand the limitations of a specific element of the game world. For example, my first character in Skyrim looked like a caveman and used his original rags and wooden bow for the entire playthrough, but I wanted to see the limitations of alchemy. I was disappointed at how powerful I got, I guess because I like strategy and it was too easy. I get there are some people who only roleplay, so balance isn't an issue. I'm more of a 50/50 roleplay and strategy gamer.
As for the barter system, I can see it being fairly efficient. If you have ever played civilizations, it could be like the diplomacy trading system they have, allowing you to make quick trades but also involved negotiations if you want.