> Imagine how tedious it would be even to use a relatively simple discussion forum like HN if you had to wait for a full page reload every time you hit a voting

> Imagine how tedious it would be even to use a relatively simple discussion forum like HN if you had to wait for a full page reload every time you hit a voting button or expanded/contracted a thread. You don't need a full page reload to implement voting; that's what the 204 No Content response is for: your browser sends the vote & doesn't refresh the page.