Using emt as a ground is not a good idea, (I'm not sure if it does or
doesn't meet code any longer). It tends to loose continuity causing
problems with the circuits. The MGM Grand fire in Las Vegas was caused by
an emt ground that lost continuity in the deli. Things heated up, and all
hell broke loose.

The Electircal Engineers I used to work with, were aware of several other
major instances of fires caused by over heated conduit grounded circuits,
and wouldn't spec or design for it, because it is a known problem and they
didn't want the liability.