Well this question came after this one
The reasons are pretty much the same, to keep the stuff cleaner, how bad is it to call (being sure the css doesn’t collide with overwriting tags)
To put <link rel='stylesheet' type='text/css' href='mycss.css'> in the middle of the body? (if it works)
So that in some cases I could have specific css for a specific module include.
<link>is only permitted in the<head>section of a document: Document relationships: the LINK element