I held this opinion strongly, but this post from Terence Eden really explains it best: https://shkspr.mobi/blog/2021/01/the-unreasonable-effectiveness-of-simple-html/
The site is down right now, so here is an Archive link:
The post argues a pretty obvious point: Poor people with limited access to the internet on weak and slow devices should still be able to access important online resources!
Sites for people seeking restraining disorder from abusive partners, for seeking low-income legal advice, etc. Like, it doesn't impact me, because I have a strong computer with a good internet connection and great English language skills and some serious technical chops.
The post also argues the following:
If your laptop and phone both got stolen – how easily could you conduct online life through the worst browser you have? If you have to file an insurance claim online – will you get sent a simple HTML form to fill in, or a DOCX which won’t render?
What vital information or services are forbidden to you due to being trapped in PDFs or horrendously complicated web sites?
and the post concludes with a lil fact ( https://twitter.com/TheRealNooshu/status/1356191997854412802 ) that a few thousand users are accessing the Gov.UK site from videogame consoles.