DSLRs often have the ability to store both a JPEG and a raw file.
Given that the primary benefit of in-camera JPEG over rawprimary benefit of in-camera JPEG over raw is the smaller filesize, and that JPEG+raw is going to store even more data than raw alone, it seems like you're just wasting space on your card and making your workflow more complicatedmaking your workflow more complicated if you store both.
Why bother storing both JPEG and raw in camera, instead of just a raw file?