Did you know it works many places, not just the Finder, including places where there is no preview pane? (Eg with items on the Desktop.)

Did you know you can do useful things right in the Quickview, like mark up an image or PDF? Here’s more: https://www.maketecheasier.com/use-quick-look-macos/

although apps can integrate with quicklook (eg vscode/textmate for code files), there are some files that should be previewable but isn't, like animated webp or webm files.