Since version 2.38.0 you can convert the balances of your foreign & crypto currencies in EUR.

Please proceed as follows: 

• iOS: select the account you want to be converted > open the account settings (tap on the small drop down next to the account name) > enable the switch at 'Convert Currencies'
• macOS: select the account you want to be converted > open the account settings (click on the account name above the list of transactions) > Settings > set the checkmark at 'Convert Currencies'

Now you can see the converted account balance in in the list of your accounts.