Sure, you won't "need" them. But it's very likely that you'll have resources that behave very well for rest like operations - user comes to mind, for things like user profile page, user settings, user detail, etc

A rest endpoint is likely handy to use across your application without having to replicate the same serialization over and over again.

Also many frameworks remove all the boilerplate for those operations (eg. Django class views), so creating one is a really good starting point.