For me personally, I found that they help reduce the noise in the code.
I also noticed that it makes it a bit easier to "read" the code (not just visually, but "semantically" if that makes sense). As in, I think I have to spend less time "parsing" ≤ than =<, but I don't have a way of really "proving" it.
However, I am mildly dyslexic, so that might play a role in it.
That's all well and good for your personal environment. But I think it's a little crazy for a blog post that's supposed to be teaching things to beginners. "≤" is actually a different string than "<=". I think it's really misleading to render one series of characters as if it were another. For instance, julia actually supports ≤. There are others. On top of that, I don't expect a font to be able to correctly parse code. Sometimes "<=" happens in contexts other than "less than or equal".