I got some Atom Echos, configured them, and they work! I even customized my own wakeword and it worked on the first try. Thanks, Home Assistant team, for such an awesome product as Home Assistant and for fantastic documentation.
Though the Echos and voice recognition works, I'm waiting about 28 seconds between speaking and having Home Assistant respond. "OK Nabu, do the thing"...then I wait ~28 seconds and then at the same time I hear the Echo say "Done" and Home Assistant responds.
Is the delay due to the Echos being small/cheap/slow processors? They react instantly to the wakeword, but perhaps that requires less processing power because it's trained. Is the delay due to forwarding the audio content of my spoken word over the network to Home Assistant so Whisper can process it? I'm able to transfer other content over my network very quickly, and I doubt the data size of a few spoken words is very large. Is the delay in Whisper processing my spoken command?
What has your experience been with the Echos and openwakeword?
(not first hand experience but) Nabu casa is a way to support HA development, having cloud assistant is just a bonus, you also get easy external access and another bonus is that you don't need to setup the different addons to be able to use assist, while it is doable on something like raspberry 4, problem will be latency compare to nabu casa or you will need a more powerful device to be able to run them smooth. If you didn't bother to setup cloud assistant by yourself to avoid fees, chances are you will stick to nabu casa and it is a good thing as you are supporting home assistant development.