I will advocate towards manually changing the card currency, nonetheless. I have done this many times and it is not such a big hassle really and moreover it let me stay in control, rather than trusting the card own ruleset to decide which balance to use (* for Revolut, see at the bottom).
Moreover you must be alert for the possibility of an unwelcome DDC (Dynamic currency conversion) at the merchant terminal or an unwelcome FX while passing the transaction between Curve <->Revolut, something you better be cautious about.
In principle, if you let Curve pass the original currency to a multi currency card, i.e. Revolut, TransferWise debit, for which you do not hold a balance in that currency already, I think it is generally okay, FX will happen anyway so you do not care that much. But, if you do hold a balance and you want to use that balance, it starts getting tricky. What exactly is to happen?
- Say, for example, that you want to buy in CHF with Curve and use your Revolut CHF balance for it.
- To start with, your Curve is most likely identified by the terminal as of GB origin from its BIN (bank identification number). -> First checkpoint, remember not to opt for DCC, because then the merchant terminal will FX CHF->GBP.
- Let us assume that you passed the first checkpoint and opted to pay in the original currency, in our example CHF.
- In this case, it is more than likely that, Curve will pass the CHF amount to Revolut to be paid in GBP (in our example, this is the base currency set inside Curve for Revolut). Then, Revolut own conversion priority rules(*) kick in and the conversion path is not as easy to predict. I believe that Revolut will spend from your GBP balance (or FX to GBP) rather than paying with your existing CHF balance.
I am fairly sure that someone can experiment and figure what happens right, but for the hassle of all this uncertainty, again, for me safest and simplest way is to take the few seconds to manually set your underlying card currency, per occasion/use, and in doing that to keep full control.
The card selects which balance to use in the following order:
*The local currency of the merchant/ATM e.g. if you are in Spain, it will deduct funds from your Euro balance.
*Your base currency - i.e. if you used a UK address to sign-up, your base currency will be GBP.
*Your largest balance.
You need to have sufficient funds in one single balance in order to make a transaction. If you don’t have enough funds in the balance of the local currency, it will default to your next largest balance and so on.