The quote seems to be from this page for the current version of Photos: macOS - Photos - Apple
Browsing this page on the Wayback Machine I can see, that the text about "Warp" and "Collage" has been added sometime between June 2018 (https://web.archive.org/web/20190601100228/https://www.apple.com/macos/photos/), where it is still missing and May 2019, where it is already mentioned (https://web.archive.org/web/20200501094632/https://www.apple.com/macos/photos/). It coincides with the introduction of photo editing extensions, so it may simply be a very ill-phrased description of the power of extensions.
The preview of Monterey is mentioning collages as well, but not as part of the Photos.app as a printable collage: macOS Monterey Preview - New Features - Apple
Collages are offered for messages and memories:
Photo collections
Enjoy multiple photos as beautiful collections in your Messages conversations. A handful of images appears as a glanceable collage and a larger set as an elegant stack that you can flip through. Click to view them as a grid and easily add a Tapback or inline reply.
...
Memories: Fresh new look
Memories has a fresh new look including animated cards with smart, adaptive titles, new animation and transition styles, and multiple image collages for a cinematic feel.*