Huh? It's just so obvious I didn't think it needed explaining. Don't you think there are literally millions of smartphone users who appreciate and use Siri and Cortana?
Anyhow lets play captain obvious. For me one of the most functions is making a phone call without interacting with the phone, for example when I'm driving. I am aware that google now provides this function to a certain extent, but it seriously pales in comparison to Siri, it's just goofy for lack of a better term. Sometimes I get google now, other times I get this weird Google voice dialer which I have no idea why or how to turn it off. Google now handling phone calls is hit or miss, my best example is "call Mario", half the time it does an internet search for super Mario brothers. That's the issue is that it's forcing an internet search down my throat when I have no need of it, I just want to make a phone call. The same is true of other functions, you get that internet search shoved down your throat. With Siri it doesn't do that, it knows you need to make a phone call and with no nonsense does that perfectly EVERY time.
Also that goofy google voice dialer is actually worse than Samsung S-voice, which is saying a lot because S-voice is atrocious. With the google voice dialer it almost never picks up when I append "mobile" or "home" to my request, so I end up doing redundant things, here is an example of calling:
Google now: press Bluetooth button, have a VERY loud chime, wonder what damage it's causing... "call Mario mobile" internet search for super Mario bros, reach out to my phone and cancel it, start again, loud chime again, hope it goes through, it finally goes through on my 3rd attempt, "call Mario mobile", which number would you like to dial yadda yadda another 30 seconds of my time wasted, say "mobile" wait for confirmation yadda yadda... finally call goes through.
Siri: press Bluetooth button, nice chime same as system volume... "call Mario mobile" instantly calls the number, no nonsense, no issues.
Now I understand google now is not meant as a personal assistant, but that's my entire point. Fix it to be a personal assistant when I need it, OR invent a personal assistant for the Android OS.