I have the Nokia E66 as a work phone. Since the bluetooth stack in the N900 has been proven to be very buggy causing choppy and useless sound I couldn't use the N900 to connect to my car speaker so I use the work phone in the car instead. In that phone I use the voice dialing function (without voice learning) and it actually works like a charm even though I have swedish contact names in my phone. In that way I never have to use my hands to dial while driving. So, when nokia fixes the bluetooth stack (I will check after the update today), it would really come in handy to have that smart voice dialing in the N900. I would of course prefer to pair my private n900 with the car bluetooth speaker instead of my work phone.
So you see, a feature like voice dialing could be very useful when it comes to safety in traffic. I sometimes see people driving while pressing keys on their phone, driving like they've been drinking a bottle of whisky. Here's the usual look in my face when I see that: