1. Yes. miniDV cam is the way to go. More flexible and reliable.
2. Some like to store their edited footage in tape medium - preserving its quality in a reliable medium. Storing in hard drive in DV would take too much space and hard drive is also often prone to failure. Putting it as DVD or VCD would involved compression which would means some loss in video quality. Having a way (DV in)to store an edited footage in DV format to tape is an advantage from this point of view.