Working sometimes is maybe more frustrating than something that never works. At least with something that never works, you know what you’re getting, but with working sometimes, it can be very frustrating.
With voice, “sometimes working” means we will find a way to bypass it. If it’s a Skill, we’re done with it. If it’s a call center, we’ll be pressing 0.
If you’re not being understood, you want to get to the stage of being understood as quickly as possible. That’s why sometimes is never better than never.