Ugh. I hate this voice stuff. It’s been around for 20 years, and it never works. It’s vaporware.
Your mileage may vary depending on which device and service you use. I use Siri, and enjoy it. My daughter likes the one on Android. I'll be driving, and without taking my hands off the steering wheel, tell Siri to "send a message to my wife", then dictate it, and say "send". Then when the reply comes back it'll dictate it to me. Works great for me. Not vaporware for me, I use it daily.