It's simple lifecycle and lightweight mechanism to be able to create complex dynamic data models easily. It’s a pure JavaScript library as it works with any server or client-side technology. The way HTML DOM elements are linked to the model using a very simple syntax, using a data-bind attribute. Using this feature, it’s made easy to achieve responsiveness. Able to create custom bindings inside data bind. Also Dependency Tracking feature which Tracks data changes in the KO attribute automatically and updates the respective affected areas. It is a best way to build complex UI structures. Knockout implements customized behaviors in just a few lines of code as new declarative bindings for easy reuse. When a change is made in the view model, it automatically changed in the UI and vice versa. It Respect HTML & CSS, it does not bring markup codes into JavaScript code, that is, HTML and JavaScript is completely separated.

It is JavaScript which also used in frontend, i don't need to learn other language, a lot of npm packages, enough support, I can debug my application quickly

Fast server, routing, templating and debugging