CF can make a fine pressure vessel it's just difficult to build and they require constant inspection that OceanGate didn't perform (and ignored evidence from their own monitoring system that the PV was responding differently to pressure after a hard bang it suffered when docking in one of the last few dives). SpaceX already has experience building the COPVs that Tesla is probably using and knows their limits pretty well though I don't want to be standing near one in a major crash either.