I don't know, if your slides are just a few keywords in a few bullet points and the occasional picture / diagram, WYSIWYM is great.
I agree that you shouldn't turn an actual article into a presentation though.
LaTeX has all the tooling to write high-quality ones.
Drawing every single figure by hand with a graphical tool is not at all something I'd even consider.
Most students, and many researchers use Overleaf nowadays, though.
Usage level is not correlated to "rate". Sometimes people use stuff because they have to, not only because they like it. See the Microsoft Word case.
I'd agree that LaTeX has fell a bit in popularity this days against Typst - but not much in its usage. It is still the de facto standard of scientific and technical document typesetting.
Perhaps it's a programmer thing.
Don't you need to insert tons of `frame` environments to get anything worth looking at?
Have you considered writing pandoc-style Markdown that's converted to TeX for typesetting? If not, have a peek at my text editor:
* https://keenwrite.com/screenshots.html
* https://www.youtube.com/playlist?list=PLB-WIt1cZYLm1MMx2FBG9... (see tutorials 4 and 9)
KeenWrite basically transforms Markdown -> X(HT)ML -> TeX -> PDF, although it uses ConTeXt instead of LaTeX for typesetting because ConTeXt makes separating content from presentation a lot easier.
These days I usually default to pandoc's markdown, mostly because the raw text is very readable.