And not every trading transaction with modern financial products is driven by the search for maximum yields in proprietary trading. If a bank closes a currency hedge deal for a customer who is active in international trade, this has a sound real economic basis. In that case, investment banking serves the customer’s interests. Nobody can really have object to that, either.
A bank whose business model is targeted at export-oriented customers will have to provide this kind of service, otherwise its business model will not work. And it will obtain commission income that should be in reasonable proportion to the services rendered. The same is also true, for example, of M&A consultancy services.