Small businesses rushing to advertise on ChatGPT could end up making expensive marketing decisions unless they understand one major difference between AI search and Google, according to ecommerce SEO expert Thomas Phillips, Founder of DTC SEO.

OpenAI has rolled out conversion-optimised advertising inside ChatGPT, allowing advertisers to optimise campaigns towards purchases, sign-ups and leads rather than simply paying for clicks. The platform has also introduced flexible campaign budgets, allowing spending to increase on days when its AI predicts stronger conversion opportunities.

While the update has been widely viewed as ChatGPT’s biggest challenge yet to Google Ads, Phillips believes many businesses risk misreading the results.

According to Phillips, conversions generated through ChatGPT are likely to appear stronger than Google because users often arrive much further through the buying journey.

Thomas Phillips, Founder of DTC SEO, said:

“A lot of businesses will look at their first ChatGPT campaign and think it’s outperforming Google overnight. That could be a very expensive misunderstanding.

Someone asking ChatGPT, ‘What’s the best standing desk for someone with back pain under $300?’ is much closer to buying than someone searching ‘standing desks’ on Google.

Those users have already researched the problem. They’re looking for reassurance, comparisons and recommendations before making a purchase.”

Rather than comparing conversion rates alone, Phillips says businesses should evaluate how each platform supports different stages of the customer journey.

He recommends marketers track:

• Cost per acquisition, not just click-through rate
• Assisted conversions across multiple channels
• Average order value
• Customer lifetime value
• Brand searches following ChatGPT exposure
• Returning customers rather than one-off sales

“The biggest mistake businesses could make is moving their budget away from Google simply because ChatGPT appears to convert better,” Phillips said.

“They’re serving different moments in the buying journey. The smartest advertisers will use both.”

Phillips also believes the update marks a much bigger shift for SEO.

“For years, businesses have focused on appearing when somebody searches Google.

Now brands also need to think about whether they’re visible when somebody asks an AI assistant for advice before they ever visit a search engine.

That’s why Digital PR, trusted expert commentary and genuinely useful content are becoming more valuable. AI platforms don’t simply rank websites. They recommend brands they trust.”

Five things businesses should do before advertising on ChatGPT

• Don’t compare conversion rates directly with Google
  Users inside AI platforms often have much higher buying intent.
• Start with a small test budget
  Gather meaningful data before shifting spend from existing channels.
• Measure assisted conversions
  Many customers will still complete their purchase elsewhere.
• Invest in brand authority
  Brands that are recognised and frequently mentioned online are more likely to benefit as AI discovery grows.
• Keep Google in the mix
  AI advertising should complement existing search activity, not replace it.

Thomas believes the businesses that benefit most won’t necessarily be those with the biggest advertising budgets.

“The winners will be brands that understand where customers are making decisions, and that’s no longer happening in just one place.”

Thomas Phillips is the Founder of DTC SEO, an ecommerce SEO consultancy specialising in search strategy, Digital PR and organic growth for ecommerce brands