Earlier quoted context omitted.
Also, it can conveniently turn your run-of-the-mill XSS bug into remote code execution! Welcome to 2016, everybody.
I am a person who always wanted to develop native desktop applications, but ended up developing for the web instead because the barrier to entry is lower. Now I have the opportunity to do what I actually wanted to do.
As you said, Electron clearly has its advantages. But I appreciate the effort when a developer creates an application using the target platform's native language, frameworks and usage patterns (in this case, Swift, AppKit and the Cocoa APIs). The result is, in my opinion, clearly worth the effort and a wonderful piece of software to use.