With multiple audience types, delivering the right content has always been important. Marvin doesn't believe that the automated migration is a reliable solution to move custom audience views for different stakeholders, regional groups, or content categories. A concern is the audience won't move over well.

This may impact publishers’ ability to understand their audience’s interests or content exploration throughout the website.

Google calls out in it documentation that while the company will create the equivalent audience in GA4, if possible, it may not be a perfect fit.

"If specific audience attributes like events aligned to audience criteria do not move over from UA to GA4, this could lead to a break in the audience, and then a break in the targeting associated to that audience," Scott said. "It’s also worth mentioning that Google itself advised against the automatic migration -- recommending businesses migrate their account manually."

Since most publishers rely on-site advertising as a revenue stream, "I cannot emphasize enough how crucial it is that ad tracking is set up properly to measure conversions and offer paid advertisers insights into the types of people and content converting on-page to inform their content syndication, bidding, and campaign strategies," Scott said. 

Publishers need to have a way to reliably drill into audience, conversion, and attribution data at a deeper level. The advantages of customizing GA4 instance to gain insights needed to advance business are too important to accept an automated migration -- and marketers will spend time and resources later trying to customize and sort it all out.

Earlier this week, Google announced support for accelerated mobile pages (AMP) in GA4, rolling out to publishers. This integration previously only existed in Universal Analytics, so bringing it to GA4 allows for parity and helps publishers make a seamless transition.