Attributes are not the same as the tag they are in.
<link /> is an empty element, i.e. it can not have anything inside of it. All it does is specify a relationship with another document. Additionally, the <link> tag is only used in the <head> section.
<a></a> on the other hand, is not an empty element and specifies an object to be created on the page – like a clickable link or image – which takes the user to some other location. This tag is only used in the <body> section.
So, even though the tags can have the same attributes, that does not mean they do the same thing.