Agreed, although for a few extra $ you can get a combined smoke/CO unit, and these are now recommended by the ABYC for all "designated sleeping" areas, the galley AND the heads. I guess they don't want you falling asleep on the throne due to CO....
The ABYC also wants these units to be approved for marine service, which I assume would mean elimination of metals in the unit that could corrode. It also means paying twice what the thing is worth, but that's another story.
This rash of fires has prompted us to begin throwing the main switch on the starter batter when we leave the boat, since it is unfused, unlike the house bank. More psychological comfort than practical, I suspect. Sailing to Hawaii a few years ago, I noticed smoke pouring out from behind the electrical panel on our sailboat. Turned out to be the propane sniffer, which was fused, but shorted out and started to burn the PC board nonetheless. On that boat, because of how small it was and the fact that it happened in daylight, the problem was immediately evident from the smoke and smell. On a larger boat, I don't know what would have happened, but the middle of the Pacific is no place to find out.