Money kept in your BRD Ethereum or ERC20 token wallet is always stored as cryptocurrency. The app uses an exchange rate to show you an estimate of how much your ether or ERC20 token is worth in your local currency. When you send a transaction and enter the amount to send in your local currency, the app uses the exchange rate to calculate how much ether or ERC20 token to send.

It's possible people using other wallets are using different exchange rates, so the balance sent/received might be slightly different than what other person sees.

Since the exchange rate is always changing, the amount of money in your wallet as quoted in your local currency may change over time. However, your ether or ERC20 token balance will not change unless you send or receive funds from your wallet.