The goal is to write small, clean, accessible HTML that works on any device, any browser, any screen, even without CSS or JavaScript. A smolwebsite should load on a smartphone from 2010, work in a text browser like Lynx, and be readable on a Braille display. Not because those are common cases, but because if your page works there, it works everywhere.
Be aware that a site shouldn’t look too barebones. Users will think something is broken and won’t even bother reading it.