In that system you can tell what is going on by looking at in a glance and works with no power. Sometimes simple is a great answer.
However, I can think of one reason the 'no power' argument fails. They do a lot by radio. That needs power. Also you would need to retrain everyone. Oh and you probably would get locked into one company that wants to control the whole software stack and sell tons of support.
When my home was built in 1999, I poured over all the home automation systems. I opted for conventional wiring. But I did wire every room (myself) with cat5 cable and RG6 coax, in a star configuration. It has served me very well, no problems at all.
I don't use the RG6 anymore, as my TV service comes over the intertoobs now. The cat5 isn't supposed to work with gigabit equipment, but it works fine. Wifi has improved by leaps and bounds, but I still rely on hardwired ethernet, as it is stupid reliable.