Yes, there is benefit to pairing them. The recoil reducer would lessen the muzzle rise and impact on the shooter. The reduced weight of the BCG has been shown to reduce the bolt bounce on return. This can aid in speed shooting.
https://www.opticsplanet.com/dpm-recoil-buffer-assembly-for-m-16-ar-15-223-5-56-calibre-rifles.html