Is it profitable to trade currency as a swing?
In trade, currency can be seen as a value that is used for paying for goods or services. It is a means of payment. As an example, some people pay monthly bills using a credit card. The service provider then pays the bank who then pays the credit card issuer. It is, but only for traders who do not take the fluctuations into account; the market does not swing in the same way.
In the long run, it is not profitable, however, in the short run it is profitable. There will be a period when the value of the currency goes up and a period when the value goes down. In the short run, you will make more money selling your currency if it is more valuable. In the long run, you will make more money selling less currency if it is less valuable.