If my agency has their own barter firm …
why wouldn’t I use them?
Because the client misses out on the additional benefits that naturally accrue to the client whose agency is “competing” with and making it tough for the independent barter firm. That competitiveness doesn’t exist with their owned barter firms. And once they bring in their barter firm – at the expense of true competition – they pretty much have to make sure everything runs smoothly or they risk being accountable for the problems they created.
The natural rivalry created between ad agency and independent barter firm leads to the delivery of a more scrutinized, better scrubbed product. The fact is that the ad agency sets the bar for all the qualitative and quantitative decisions and they are MUCH tougher and MUCH more demanding with an independent firm.