Well. The point here is that a bank "emit" EUR asset, and another bank USD asset, these are "anchors". They fix something outside the stellar network to an cheap to send stellar asset.
Stellar has its own distributed exchange. So you could buy EUR asset with real EUR, exchange EUR asset->USD asset, then sell USD asset by real USD.
It is like USDT (tether), but, with a distributed exchange.
Commissions here will be the ones the 2 anchors takes to do €$ - €$ asset, and the 0.00001 stellar.
That last thing is the main difference with ripple. In ripple the coin is not required to transfer assets at all, so everybody investing in buying ripple has the risk that it will not be used later, as is detached from the network.
In stellar, XLM are attached to the network, they are required and buying them is a way to support this project. After all,every system will require a maintaining and somehow it should be paid, it is also a way to protect the system from spam. As anyone could be able to create asset and spam the network if there is not a fee in a common asset.
There are some anchors there already, but not enough in my opinion, and with hard process to sign up. The point will be that a global halcash company parner with stellar. That would change everything. Of course, even a central bank could join stellar, issuing an asset in the network.
Hope i explained it well.
Even if price is quite low, i will keep working for stellar, as it is compatible with an idea i had some time ago. And i hope i can develop once.