What is the Shari’ee status of purchasing currency on a forex Wallet app?

Our understanding of the forex wallet in question is as follows:

Through the app you are able to purchase forex from Standard Bank. Assuming you purchase $100 for R1410,00, if the current rate is R14.10 to a dollar, then $100 is credited to your bank account, which is referred to as a “currency wallet”. Once your currency account is credited with the $100, you are free to utilise the currency either by physically withdrawing the currency, or purchasing with the currency at local stores and abroad. You also reserve the right to resell the currency if you wish to do so at any given point in time, either to Standard Bank, or a foreign exchange of your choice.

If our understanding of the system explained above is correct, then dealing in forex in the above mentioned manner will be permitted. If the system is any different to what we have explained, then we request you to provide the relevant details and we will respond accordingly Insha’Allah