Yes — it can still be useful with a DSLR, even though you probably won’t use it exactly as it was originally designed for film.

The key difference is that the Zone System is a way of previsualizing the scene: it helps you decide how bright different parts of the image should appear and how the scene’s tonal range should be placed in the final photo. The histogram, by contrast, shows what the camera actually captured.

Used together, they complement each other: the Zone System helps you predict and intentionally place tones, while the histogram helps you verify the result and see whether highlights or shadows are clipping.

So the value in learning it is less about following the classic film workflow and more about training your eye and improving exposure judgment. Many photographers find it useful as a general way of seeing tonal relationships, even for color digital work.