Sorry still don't get it. I'm using a Win7 laptop & Chrome. I click on the link button, it gives me the opportunity to paste in a link. I have to copy a link, so I might as well paste the link directly into the window, rather than pasting it into the box the link button throws up.
Regardless of how I set the link up, it's still just a click for the person reading the post, so I don't see why it irritates folks if I don't use the link button?
Don't understand the comments about iPads – is the link button to make life easier for iPad users?
I'm feeling exceptionally dumb this morning 
Steve