From my crappy memory, GIF was developed for the CompuServ online service.
The 89a specification that you immediately mentioned was an extension of GIF in, 1989.
Thinking up things or imagining them, doesn't mean it exists.
So, in GIF facts, it was not developed or intended for HTTP (World Wide Web) use. It was however, a nearly universal standardized image format that meshed perfectly with the advent of HTTP. With gigabytes of already available content and tools.