Keynote is great if you are making a presentation for yourself and you don't need to share or collaborate on it. Otherwise, interoperability trumps features, and either Google Slides or PowerPoint is good enough and more likely to be compatible with your collaborators. It is sad, I'd love to use Keynote too, but the sharing barrier is just not worth it in 99% of my use cases.

edit: I think Figma slides has an uphill battle ahead for the same reason.