Attribution
Customers generally prefer to understand prices in a familiar local currency. Your internal advertising account can still operate in another currency. The important part is keeping the customer-facing price and tracking values consistent.
A UK shopper shown €84.63 has to translate the price mentally. Showing £72 is easier to evaluate.
Merchant Center price, ad price and landing-page price should align according to Google's current requirements.
If you hard-code a dollar price into an ad shown across several countries, the website may display something different. That creates message mismatch.
The event should represent the actual transaction in the intended reporting currency according to your implementation.
Meta can report spend in the ad account's currency while Shopify sells in multiple currencies. Business reporting needs normalization, a point that also drives how currency differences affect ecommerce ROAS.
Use local currency for customer clarity where the store supports it, then make sure measurement translates those transactions consistently.
If international pricing is creating mismatches between ads, Shopify and reporting, contact us. We can help standardize the setup.