I cannot right click and save an MP4 video in my browser.

I cannot drag and drop it into an email.

As a regular end user, I can use approved sharing features only. As a developer, yeah, I can download it myself and rehost it somewhere that hopefully supports MP4 video.

The historical pissing match over how to best do animated PNG files is sad. An animated image format that is treated differently from videos is a nice thing to have.

People have entire folders full of appropriate reaction GIFs. With how MP4 video is treated online today, such a thing is not possble.