I often wonder why was the marquee tag deprecated

It was gone in a <blink> of an eye.

@kescherRant but there are still lots of tags that include some sort of style, like b, u, i.
other tags have a general basic style like div is by default always width:100%

anyway, marquee still works kinda everywhere despite being deprecated since 2008 at least

Em, b, u, i, even though they control style, still have a semantic meaning. They all emphasize text in some way. If only visual aspect is important use CSS. If you have something to point out differently in meaning use html.