Nobody cared at allThe mods cared. There were many bots used by moderators that relied on karma, the main one being automoderator.
mp4 is a video format, the key differences with animated images being autoplay, looping and maybe transparency.
Of all the formats you mentioned these are supported on popular platforms:Twitter: gifDiscord: gifMastodon: gifReddit: gif, apngTumblr: gif, webpLemmy: gif, apng, webpThat's why gifs are still a thing.
The fact that GIF is still a thing in 2023 is bafflingAs opposed to what widely supported animated image format?
Your link talks about the element zapper, the icon that looks like a lightning. The instructions above talk about the element picker, the icon that looks like an eye dropper.
The mods cared. There were many bots used by moderators that relied on karma, the main one being automoderator.