QYLD Questions?

Could someone explain how the ROC works and why people say it is bad?

Is this why people are against QYLD?

I have read a fair amount about it. But I don't understand why there are so many people against QYLD. If I am going after dividends and reinvesting them for now, then what is the issue? Just that claimed losses won't be there later if the price drops?

If I buy 5500 shares at $18/share, then what is the downside to leaving it there for a few months? or long term?

(Besides the obvious share price going down)

Thank you!