General currency conversion question and account type

If PayPal are showing this USD 140 to Euro 130 automatically, then from an accounting perspective you should only be taking up the Euro 130 as the transaction, as its only a single but converted transaction.

If however, the USD 140 was an accumulation of transactions, which you then transfer in bulk via a separate transaction, then you would take them up separately.

As an aside, you can’t use the Bank Transfer feature under these circumstances, they need to be processed via separate Receive & Spend Money transactions.

NOTE: you would only use multi currencies if you are actually storing values within the currencies - but not if the currency is being past though without storage.