I'm not 100% sure if assistive technologies use section and article for any end user context like "jump to content", but they at least can be used to get more context than just another div
Reader mode is one I don't think about enough. I could see that purposely hiding content outside of the article element.
Yeah, Reader mode is weird. I know it prioritises semantic tags like article, but since the behaviours are not standardised, I never know what will and will not work.
