Not sure I understand how it demonstrates BiDi problems.

The real BiDi problems come when you got a context of LTR in RTL.

For example:

אני חושב שזה cool לכתוב מילה באנגלית.

This is where things goes wrong. And we didn't even start with text selection...

nah, if you use `unicode-bidi: bidi-override` and force `direction: rtl` it'll still flow top to bottom. a conlang I speak is cursive RTL so I've made extensive use of this. side-note: it's a major peeve of mine that Unicode's entire Private Use Area is plain Latin in terms of properties. there's no way of setting RTL other than using CSS or prefixing an RTL Override character, which gets old fast in text editors. no font system, including Graphite, lets you override Unicode glyph properties to my knowledge.

> I don't think there's are any bottom-to-top?

There are philipino and indonesian scripts which ars written bottom-to-top, though they are read left to right.

Ogham is bottom to to though.

I think there’s also a script which is read and written based on cardinal directions, but i can’t find it. I was expecting it to be indigenous australian (as several IA people use absolute directions as a matter of course).

What exactly due you mean by "West Asian"? Georgian and Armenian are left-to-right.

Because then the site would not demonstrate the pain caused by poor RTL support, as most of its target audience will not be able to make sense of the script.

The point is that even when you understand the script and the language, you find yourself looking at a website with messed up formatting, punctuation in the wrong place, and broken sentences when BiDi gets involved. Those of us who deal with this all the time are used to it, but most people have no idea how broken things are.