Traders and investors are the real customers, not merchants and shoppers. Merchants and shoppers don't necessarily need to hold bitUSD for a long time to do transactions. Nor do people using bitAssets for remittance purposes. These people hold bitAssets for as short a time as possible. They just want to be in the BTS system to accomplish their transaction. Then they leave the system.
In contrast, traders and investors either:
a) make lots of short term transactions (requiring frequent paying of fees) OR
b) hold their assets for a long period of time (taking those BTS out of circulation and also generating a yield that must be paid in BTS)
But traders are not interested in BitShares. Why? Just compare Bitshares to non-Bitshares trading platforms. Foreseeably, the most popular market-pegged assets will be government currencies, cryptocurrencies, and stocks. In the non-BitShares world, the most popular platforms for trading those assets (Forex markets, cryptocurrency exchanges, and stock brokerages) all have one thing in common: there is borrowing. The less volatile the asset (e.g. government currencies), the more borrowing is allowed. (Because no one is going to trade bitEUR:bitUSD unless they can trade with 20x margin.) The margin levels of course should differ depending on the class of assets traded (e.g. bitEUR:bitUSD should allow for 20x margin but BTS:bitUSD should only allow for .5x margin.)
The ultimate vision for BitShares, which I think we all share is:
Any person anywhere in the world with 100 BTS can hold, trade, borrow, or lend every major asset that exists in the world 24 hours a day, 7 days a week, 365 days a year with zero counter-party risk, virtually no minimum deposit or withdrawal size, low fees, and total privacy.
Trading is the activity that BitShares excels at. We want this to be like a vacation resort; people come into the BitShares system with their $2000 and Bitshares offers so many amazing services that they spend that money playing in the Bitshares system for years while they borrow, lend, daytrade, and invest to their heart's content. Mr. Larimer is a BTS bull so he shorts bitUSD, bitCNY and every other currency into existence in exchange for more BTS. Mr. Bernanke is a stock market bear and offers to short the entire US stock market against his bitUSD offering 0% interest. Ms. Zhang from China wants to buy Berkshire Hathaway but it's not available on the Chinese stock market. Ms. Zhang gets some bitUSD and buys bitBRK from Mr. Bernanke. Mr. Volker risks lending Ms. Zhang some additional bitUSD at 10% annually as long as she is only allowed 3x margin or less and will be automatically margin called if her balance goes too low. Mr. Gates knows something about what bitUSD:bitMSFT will do next week and no one's going to know if he trades it. And Mr. Ackman thinks that the USD:Hong Kong dollar peg will break and the Hong Kong dollar will be worth 30% more after the peg breaks. So Mr. Ackman borrows 50 million dollars worth of bitUSD at 10% per year and buys bitHKD. And he will pay the bitUSD back after the peg breaks or he gives up.
And it goes on and on and on. Are you guys seeing what I'm seeing? BTS will eventually be like like forex, Bitfinex, NASDAQ, Nikkei, and Hang Seng all combined, only better. A one stop shop for trading anything and everything. And then we just make sure there are no clocks on the BTS client and let people waste away in front of their computer screens making trade after trade in complete capitalist ecstasy burning up fees while simultaneously soaking up BTS supply (into bitAssets).
When BitShares can do this, the CPC (cost per customer) that we are so worried about is going to drop to 0 because BTS will be more addictive than World of Warcraft.
tl;dr - Forget about merchants and customers. We need collateralized lending markets to attract forex, cryptocurrency, and equities traders and keep their money in the BitShares system.
EDIT: made my examples more accurate