Currency Exchange or Virtual Currency Wallet?

Hi,
i am building a service where content can be bought and sold.
Now as this should work for multiple currencies, i had 2 ideas to solve the problem:

1. handling the currency exchange by myself and display the price always by exchange rate
2. all the currency on the wallet gets instantly exchanged to some virtual currency and within the whole service, just the virtual currency will be used.

Is there anything against a virtual currency?

Thanks for your help :)