Yes — a supplier can quote in a currency other than the Pricing currency you set on your demand, and within a single offer they can price each line, and each cost such as freight, in its own currency.
On the offer screen the supplier has an Offer currency (comparison currency) field. It defaults to your demand's pricing currency, but the supplier is free to change it. Changing it never disturbs the figures already entered; it only re-converts the total.
None of this lands on you as a mess. Lines and costs quoted in other currencies are shown converted into your comparison currency, so every offer you receive reads side by side on the same footing. The conversions on screen are indicative; the rate is locked the moment you accept an offer.
If you want to signal a preference up front, fill in Acceptable currencies while opening the demand. The currencies you pick are shown to suppliers in the demand summary above the offer form. Leave it empty and the supplier picks their own.
Also asked as: Can a supplier quote in a different currency? · My demand is in EUR — can I get a USD offer? · Can each line use a different currency? · Who chooses the offer currency?