This feature is fairly useless, and it was probably added to the browser by a tired programmer working on a buggy piece of software, and wanted something stupid and foolish that no one could possibly care about. Or equally possible they thought it was "cool" and thought everyone would be psyched about where it would lead. They could get their names in the history books as a great inventor. They were really weird times and people had all kinds of ideas, but then programming was still programming, often a thankless slog. :-)
However I think it's really cool that I'm writing this test code in 2024 and the marquee element still works. That's the web way to go. I like the fact that any website that used this feature in 1994 still works today. I bet they had endless meetings at Apple, Microsoft, Netscape, Sun, Adobe, Google, the W3C, IETF, who knows, arguing about whether to keep it, and every damned time they decided to keep it. It wasn't hurting anyone. And if it broke in a release, the developer who had to fix it will have learned about importance of continuity. There are way too many programmers out there who think breaking users is okay. I belong to the other school, even have a motto for it -- Discontinuities suck.
Anyway, I hope this demo app still works thirty years from now in 2054.
7/13/24 by DW