That euro conversion stuff doesn’t matter if the US won’t deal with any bank that interacts with the Cuban currency. That’s what an embargo does. You’re right it’s not hard to exchange currency. The entire point of an embargo is to function as a financial seige, to prevent the economy of the embargoed target from growing through mutual trade with the literal financial hegemon of our world.
It’s just how basic demographics analysis works. There’s a lot more people who are struggling with mental health problems/mental disabilities that make them more prone to believing scams. And so many games and storefronts use dark patters to make it extremely easy to make undesired purchases or have no safeguards to prevent children from using their parents credit card for purchases.
All these kinds of people vastly outnumber dumb finance bros on their yachts making stupid money decisions.