While I pretty much agree with you that microbenchmarks are always suspect, it's also worth noting that HTTP2 will change the landscape a bit. All those bundles of icons in fonts and sprites can be loaded in parallel going forward...so, lots more very small files.
Further, I rarely worry much about web server performance, because I have so many other pieces in the stack that are the bottlenecks. In fact, almost everything in my web application stack is slower than my web server...so, I don't sweat the web server, except in cases where I can find a good argument that it matters. So, a benchmark of one very fast web server against another very fast web server (and most of the major players are very fast, at this point) is not going to convince me to change.
The difference is not so obvious when file size increase compare to nginx.