The problem is that µ is usually hard to type (unless you have a Greek keyboard or a custom keyboard mapping). This said, although I tolerate stuff like "47 uF" in electronic schematics (also because legacy software didn't even allow the µ symbol), I definitely find horrible to see stuff like "us" instead of "µs" in an article.

I just googled it to type my comment. And if you're using it enough to need quick access, you can do alt + 0181 on your numpad on a windows system