...
What’s the impact on users of Google Analytics in Confluence
The only impact is that the configuration step will need to be repeated in Confluence CloudGoogle Analytics reports displayed in Confluence for specific content (pages/blogposts) may no longer display historical data. This is because we cannot assume that the contentId of the page/blogpost in the source Confluence Server system is not guaranteed to be the same as the contentId in the Confluence Cloud instance.
Google Analytics will still provide the historical data, so it will be accessible in custom reports there.
Details of the configuration process can be found in Configuration Overview.
...