Interest rate swaps are in the same currency. In an interest rate swap, we were concerned exclusively with the exchange of cash flows relating to the interest payments on the designated notional amount. However, there was no exchange of notional at the inception of the contract. The notional amount was the same for both sides of the currency and it was delineated in the same currency.
Principal exchange is redundant.
However, in the case of a currency swap, principal exchange is not redundant. The exchange of principal on the notional amounts is done at market rates, often using the same rate for the transfer at inception as is employed at maturity. They are using the Swiss Francs to fund their US operations. The only rationale for doing this is because there are investors with Swiss Franc funds who are looking to diversify their portfolios with US credits such as Acme's. Because this issue is funding US-based operations, we know two things straightaway.