ROAS Isn't Profit: Why Japanese SMB EC Needs Gross-Margin-Aware ROAS

"ROAS is at 300%, so we're profitable." I've watched this sentence get accepted in marketing meetings, signed off on slides, and used to justify scaling spend — and then watched the same campaigns produce a money-losing month-end P&L. The bug is small but expensive: ROAS at 3x ad spend can still los