Barter has its uses but its not an essential skill although you will need a high barter in order to get the Mysterious Magnum and not fail the quest.
You need to pass a 50 Barter check to get that weapon. You can get 20 points from a magazine with comprehension, 2 points from Mentats and 10 points from Party Time Mentats (which stack with regular Mentats). Its fairly easy to boost your Barter skill by 32 and further still with alcohol and apparel. This only applies though if your character has 4~ or less Charisma and if we are talking about min/max characters here then Charisma would be set at 1.
The addition of magazines devalued Barter and Speech even further because you no longer need to pump them up so high to pass speech challenges.
These sorts of games are always way off balance in terms of money. It's simply too easy to accumulate. Personally I really dislike being rich. I love the early levels where I'm struggling for cash, and when you find something valuable or recieve a reward for a quest it actually means something. There's no way I'd put points into Barter and shorten that golden period even more.
I agree. A single player RPG will always have that end game of infinite money which then leads to infinite supplies. Whats good enough though is if that doesnt happen until enough time has been spent to finish the game and then some. The first few hours of a new character is always the best because you have to scavange and make your supplies last.