About Apple Creator Studio - Apple Support
"Apple Creator Studio is a collection of creativity and productivity apps from Apple that includes Final Cut Pro, Logic Pro, Pixelmator Pro, Motion, Compressor, and MainStage. The subscription also includes premium content in Pages, Numbers, Keynote, and Freeform."
So it sounds like there will be features in the subscription versions of Pages, Numbers, Keynote, and Freeform that the free ("included with the purchase of a Mac") versions of those applications will not get.
Introducing Apple Creator Studio, an inspiring collection of creative apps - Apple
"With Apple Creator Studio, productivity gets supercharged with all-new features that bring more intelligence and premium content to creators’ fingertips so they can take their projects to the next level."
"Premium content" sounds like a feature that the one-time-purchase versions will not have. But Apple doesn't go into a whole lot of detail about what the difference between the one-time purchase and subscription versions will be.