@jasper there are a number of advantage to using s-expressions. A couple of big ones for me are:
Having a single syntax for logic and data. You can take any piece of code and transform it using the same language you're already using. I wrote about the benefits of that in detail here
https://yogthos.net/posts/2017-10-03-MovingForwardByLettingGo.html
S-expressions also allow much better editors where you're manipulating blocks of logic as opposed to lines of code as seen here
http://danmidwood.com/content/2014/11/21/animated-paredit.html