If a large share of your Google Ads budget and conversions come from branded search, your blended ROAS is probably telling you a more flattering story than reality.
What branded search actually captures
Branded search is someone typing your company or product name directly into Google. These are people who already know you, often already decided to buy, and are searching by name to find your site, sometimes literally right before or after seeing your product elsewhere. Bidding on your own brand name and "winning" that click is close to guaranteed conversion at a very low cost per click, which makes branded search ROAS look extremely strong, often 10x or higher.
Why that inflates your overall number
If branded search is blended into your total account ROAS without being separated out, it pulls the average up and masks how your actual demand-generation campaigns (non-brand search, Shopping, PMax on cold audiences) are really performing. A brand spending 60% of budget on non-brand and 40% on brand can look like a 4x ROAS overall while the non-brand campaigns doing the real acquisition work are sitting closer to 1.5-2x.
How to check this in your own account
Split your campaigns by brand vs non-brand keywords (or check PMax search term insights for brand terms if you haven't excluded them). Compare ROAS on each segment separately, not as a blended average. If brand search is a large percentage of total conversions, that's a signal your "strong overall ROAS" is doing a lot of work to hide weaker non-brand performance.
What this looks like in practice
A D2C brand with decent organic awareness (from influencer activity, PR, or word of mouth) will naturally generate branded search volume regardless of whether Google Ads is running at all. Some of that branded ROAS isn't incremental, meaning the customer may well have found you organically or typed the URL directly. Paying for a click you'd have gotten for free isn't necessarily wasted (defensive bidding against competitors has real value), but it shouldn't be counted as proof that your acquisition strategy is working.
The fix
Report brand and non-brand ROAS separately, always. Use non-brand performance as your true measure of whether paid search is actually growing the customer base, and treat brand campaigns as a smaller, defensive line item with its own, much lower CPA expectation.