Why does Pages mention an incompatible 'Image Playground' app?

Visit System Settings > General > Software Update and ensure that your new M4 Max software is up to date. I strongly encourage you to acquire an external drive and to configure Time Machine to use it for consistent backups. Ideally, that external drive should be 2 - 3 times the capacity of your internal storage.

I have read the What's New page for Pages v14.4 on iOS 18.5 and macOS 15.5 and it clearly states that after enabling Apple Intelligence on specific processors or later, one can use the Apple Image Playground application with Pages on those platforms. I expect no difference with iPadOS 18.5. The caveat is one must have an iPhone or iPad with an A17 Pro chip or later for those platforms.

What’s new in Pages on Mac - Apple Support

What’s new in Pages on iPhone - Apple Support

Create original images with Image Playground on Mac - Apple Support

Apple's Image Playground on macOS, provided Apple Intelligence is enabled, will take awhile to download its relevant content before it can be used.

There is an Image Playground named application in the Mac App Store that is not created by Apple and that may be confusing. That application is not in the iOS App Store.

The implementation of Pages on macOS is more robust than found on iOS/iPadOS devices and that must be taken into account owing to operating system and platform differences.

Image Playground is Apple's AI image creator. Apple is just advertising that you can now more easily add an Image Playground image into pages.

Image Playground isn't like other AI image generators. Nobody's ever going to get fooled by Image Playground. It's images have a certain "look" about them: