Do we ever use red/orange/yellow filters shooting digital B&W?

I'm sure physical filters aren't worth it most of the time, but it's important to understand what you're giving up by relying only on the standard RGB filters in camera.

Most of the time the camera can differentiate hues well enough that you can adjust tones as you like in post. However, there are some objects which produce the same hue in camera, but which can be separated using the right frequency filter. IR is especially useful here because vegetation reflects it so strongly. Here's an example where the green of the lily pads and of the water is very similar and, because of a shadow across the scene, is hard to separate in post.



Normal photo

Using a near-IR filter

These were shot on an unmodified X-pro1, which has a weak IR cut filter.

There's nothing special about IR: any filter which cuts part of one of the normal RGB channels, but not all of it, can be useful for separating hues that would otherwise be equal. I'm sorry I don't have examples of other colored filters, but B&W is not my main focus and I haven't experimented.