I have a very low tolerance for error in things like setting timers, playing music, getting weather, calling someone. This is because I can complete these tasks simply, quickly, and with 100% reliability by hand. The marginal improvements allowed by tools like Siri aren't worth it to me if there is any decrease in reliability.
I'm sure there are use cases I'm not considering, but I've also seen perfectly able-bodied folks shout "call Steve" into their phone for 40 seconds longer than it would have taken to navigate manually. Conceptually, the idea of stacking even more engineering onto these tools to get these tasks working reliably is funny.