Okay, but that 11% figure is mostly because of your traditional bank, which charges for deposits (wtf?)
Lets say I want to $100 to a friend in Mexico:
* My bank doesn't charge me for deposits. (still $100 USD)
* Coinbase charges 1% to convert my USD to BTC (converted 8.947 BTC at 11.05usd per btc)
* Sending that to someone else costs almost nothing (8.947 BTC).
* The person receiving is not charged anything, unless they want to convert to another currency (e.g. pesos)
In this scenario, there is certainly slippage / costs, but it still beats MoneyGram, WesternUnion, Xoom, etc in terms of cost to send money from country to country.
Then coinbase takes 1% to transfer money somewhere.
So for $3.99 = $3 deposit fee + 0.039c for 1% coinbase
= $3.04 or equivalent to 76% of the cost
For $29.99 = $3 deposit + 0.2999c for coinbase
= $3.30 which is equivalent to 11% of the cost