Mostly, no—you don’t need in-camera HDR just because a camera can shoot RAW. A single RAW file already holds more dynamic range than a JPEG, so you can often recover extra highlight and shadow detail in post.

But that is not the same as true HDR from multiple exposures. In-camera HDR typically automates shooting and combining a bracketed series of exposures to capture a wider tonal range than one exposure can hold. You can also do that yourself later, often with more control, using RAW files and HDR software.

So the difference is:

• single RAW: more editing latitude than JPEG, but limited to the dynamic range of one exposure
• HDR mode: combines multiple exposures to exceed the range of a single shot

In-camera HDR is mainly a convenience feature. It usually creates a finished JPEG automatically and makes the processing decisions for you. Off-camera processing from RAW generally gives you more flexibility and often better results, as long as the scene and camera are steady enough for bracketed shots.