That's the point. Everyone is acting like this is a magic Siri thing they're working on - it's not. It's just a trigger action. The Watch can already do it.What? No. Instead of 'hey Siri', it's using the wrist raise action as a prompt to listen. This is not the same problem at all.
This isn't a job for the Siri engineers. This is a job for the iPhone/HomePod engineers on how to find an alternative trigger action like the Watch does.
Also, anyone saying "Why not fix Siri instead of this" doesn't understand software development.