In Resilient Web Design Jeremy Keith discusses the idea of material honesty. He says that “one material should not be used as a substitute for another, otherwise the end result is deceptive”.
Making a link look like a button is materially dishonest. It tells users that links and buttons are the same when they’re not.
In Buttons In Design Systems Nathan Curtis says that we should distinguish links from buttons because “button behaviours bring a whole host of distinct considerations from your simple anchor tag”.
For example, we can open a link in a new tab, copy the address or bookmark it for later. All of which we can’t do with buttons.