It sounds extreme, but it's definitely necessary in order for a service to be treated like a tool. When was the last time your screwdriver decided to fail for undefined reasons? For that matter, how about your text editor?

For something like a voice interface to become second nature, you need to deeply trust that it'll do what you expect. Work with screwdrivers enough and they become an extension of your hand.

I couldn't have explained it better. You've nailed the core issue - Reliability & Robustness. These attributes of a product disappear in the background when it just works.

Voice activated devices, even Google assistant, are far away from the reliability/robustness we expect from a reliable tool. Therefore, they are not tools yet.

They're completely reliable for weather, specific queries like will it rain, timers and music. That's enough to be compelling at the price level.