Earlier quoted context omitted.
Why do a REST-like service? It makes sense as backend for a native iOS/Android app, and if you already have that REST endpoint then it can make sense to re-use it for the web-version of your app. But if you're not doing an iOS/Android app (most websites?), then I generally agree it's a lot more work compared to form-based / server-side-templates (though sometimes can give a _slightly_ better user experience, _if_ don…
In this day and age, mobile apps are _almost_ a must so REST is everywhere. A well-implemented REST app is pretty nice, business logic divorced from all UI and API lends itself nicely as a comfortable and maintainable programming environment. More often than not, being RESTful from the get-go tends to have positive returns down the line.
This really isn't true. Mobile apps are far more expensive to develop (everything is doubled, you're dealing with periodic forced updates outside of your development schedule, etc.) and there are a ton of apps which don't need anything you can't do in a browser.
One of the earliest things to do on a project is agreeing on what level of complexity makes sense for you. If your project doesn't have a known hard requirement for mobile apps and correspondingly large team sizes, a classic Django app is likely to let you iterate an order of magnitude faster at lower cost overall.