He has a point.
Let me explain why. There is no requirement to have USD transactions settled or even domicile within the US so this would be a particularly strange move. Let me give you an example; the LME allows you to trade base metals in 4 currencies, USD, GBP, EUR and JPY. These are cleared contracts on an exchange (CCP) that is underwritten by the UK treasury. When I settle my trade I pay or receive in the currency dominated, if the EU are saying that the EUR contract must be settled in the EU then they will run in to all sorts of legal issues. Firstly why should the UK government underwrite the EU transaction? Secondly why should non Euro zone members of the LME contribute to a default fund for any euro positions? That’s before we even think about the physical nature of commodity markets, for example say I’m long 100 copper in USD and short 120 copper in EUR I net settle the metal via LME warrants (as it has no currency) and settle cash basis the official settlement price. If I have to unpick that trade I’d receive 100 warrants and deliver 120 ... but receiving warrants happens after delivery so I’m fucked unless I hold warrants. Fortunately metal in bonded warehouses is in FTZ’s else this would be a right mess. I predict no one will trade euro denominated metal (they’ll just hedge FX exposure) if they go down this road because it’s a bloody nightmare so they’ll still end up with 0 clearing revenues.
There are similar arguments for other similar products that trade in multiple currencies.
What is going on here is a simple attempt at a land grab of the euro executions to the EU - and I understand that - but as we’ve seen with some of the issues seen with the Brexit deal, is it all seems straight forward in principle but it’s the details that get you.