One can make code more readable and intuitive and making a good product for the user. I have done both in heavy server side rendering using templates and SPA r

One can make code more readable and intuitive and making a good product for the user. I have done both in heavy server side rendering using templates and SPA rendering on the client side. It all comes down to your user base and the devices/browser they are using, if they have an aversion toward running JS in the browser. By using JS on the server side, you can maintain quite bit of logic on both server and client side. If you are doing web development, why not make it the same. Yes, one shall not trust the client validation, but many people find JS validation to be more user friendly than a form submit.