They average incompatible businesses
Different margins, price points, countries, brand strength and account maturity, collapsed into one number.
They hide the distribution
An average ROAS of 3x can be one advertiser at 8x and four at 1.7x. Which one are you?
They invite the wrong target
Aiming at a benchmark rather than your break-even means aiming at someone else’s economics.
What to use instead
Your own history, and your own break-even. Both are specific, both are knowable, and neither requires trusting a survey.