Web applications are becoming more and more powerful with the new APIs made available by browsers: Geolocation, notifications, Bluetooth, etc. The problem is that not all browsers implement these APIs at the same speed, and some even refuse to implement them at all in an attempt to block user tracking.
So how do you create rich applications when you're a web developer? For mobile applications it is possible to use frameworks like Ionic or more recently React-Native, but what is there for the good old desktop? ElectronJS and this is why you need to depend on ElectronJS developers.