No, you're missing the point. If my understanding is still current (I suspect it is) these ETFs "decay" over time. Which means you can be "right" but if what

No, you're missing the point. If my understanding is still current (I suspect it is) these ETFs "decay" over time. Which means you can be "right" but if what you're right about doesn't happen fast enough, you still lose money. That's why people suggest shorting the ETF that is opposite your prediction.