I use Apache specifically on shared web servers in order to run each customer's web site under a separate uid/gid (for security purposes). I use it on other $work web servers just for consistency/ease of management (performance isn't an issue).

Mostly I use it because, after probably 20 years or so, I'm quite comfortable with and accustomed to it.

That said, I have started putting a few of my own web sites on nginx just to try it out a bit and get some familiarity with it.