QuickTime can be used as a screen capture tool. You can capture pictures or record your screen, similar to Screencastify.
QuickTime also allows you to change your recording source, so it's great for recording your iPad screen.
QuickTime can also be used to record audio clips without video. These recordings are automatically saved as .m4a files, but can be manually converted to .mp3 files by renaming the file and changing the file type at the end. *Google Slides will only accept audio in .mp3 or .wav formats.
Similar to the Screencastify Editor, QuickTime has a simple way to merge a series of video clips into one single video.