HN's doc on formatting: https://news.ycombinator.com/formatdoc
But on other sites, yes, it's very irritating that I can't count on support for things like tables or checkboxes because those are extensions to Markdown and not part of CommonMark or the original reference everyone implemented from. Or how some sites get finnicky about whitespace around list items.
In particular, for a website that heavily covers software and engineering, it's a pain that it doesn't have a good way to format code.
``` this should be formatted as four lines of code with line breaks at every newline without having to indent every line with spaces ```
Currently people often use these code block-ish things for quoting text, for lack of a better option.
Minimal features and css are all well and good as long as they work properly ;)
For example:
I never shop at WalMart because WalMart doesn't pay their workers a living wage.