"Actually usable" seems to be going a bit too far for rhetorical purposes. I use Siri probably two dozen times a day-
-messaging people
-setting alarms
-setting reminders
-taking notes
-weather queries
-occasionally some informational thing like the time of a game (e.g. "When do the Lions play next")
-set timers
-query on the status of alarms and timers
-occasionally sunrise, sunset
-volume up/down / next / previous / skip
-phone people
It operates at close to perfect effectiveness for the real-world usage that I have. I don't expect it to ever be as good as Google as it operates on a tiny fraction of the data that Google has on the average user, but it's perfectly effective for that.
It's pretty hard to use Google assistant on an iPhone. The integration just isn't as good, and I suspect different speech models are used given that on device models depend a lot on hardware. It'll be nice to try it on a pixel phone and feel the difference yourself, but I don't know how you can do that without buying a new phone :) I switched to Pixel 3a initially for its camera and also I'm holding off a premium phone purchase until 5G comes about. I'm impressed with what Pixel 3a does with camera via better software. But what's genuinely surprising is the google assistant speech model quality and integration. I ended up buying a home mini and am planning to buy a smart display to get more of that. I'm unusual in that I don't really care about data privacy issues with Google. The convenience is worth it for me personally. But my main point is the processor benchmark matters, but it's not the only thing that matters :)
-messaging people -setting alarms -setting reminders -taking notes -weather queries -occasionally some informational thing like the time of a game (e.g. "When do the Lions play next") -set timers -query on the status of alarms and timers -occasionally sunrise, sunset -volume up/down / next / previous / skip -phone people
It operates at close to perfect effectiveness for the real-world usage that I have. I don't expect it to ever be as good as Google as it operates on a tiny fraction of the data that Google has on the average user, but it's perfectly effective for that.