[scrollaway]

If you are writing <p>something <div>like this</div><p> then your editor knows you are making a mistake and can highlight it.

If on the other hand you are not closing tags that autoclose, how can your editor tell you? There is no way to know it's not intended.

[BurningFrog]

The editor could have a setting for that.

But mostly I meant that you don't have to close the autoclosing tags.