Links result in the browser showing a copy of the URL in one of the corners superimposed upon the website body context. This is the thing that corporate HR tells boomers to read to trust where a link is taking you.

Buttons, while still allowing you the same arbitrary navigation control as links (provided you are fine with JS) do not result in the browser showing an HR approved URL preview. This allows the developer to make their own which says whatever the fuck they want thereby easily tricking boomers.

As far as I’m concerned this is the only relevant difference. (Not that there aren’t other differences, but none that are as relevant as a built in easily exploited attack vector that corporate HR continues to peddle incorrect narratives of).