When you capture straight to hard drve, you will be capturing to dv tape at the same time....
the rationalle is to avoid having to import after shooting. your tapes go untouched unless something goes wrong.
  you grab afew highlight clips to put in your show. not actually editing,  but it does work and is alot of fun.
don't forget, what I do is alittle diferent. we do video and stills. There's not alot of stills to be shot during speeches or dinner, so there's time to assemble a quick show. soon we'll be doing the music as well, so we'll video jockey the whole reception and run our own photo and video clips to the beat of the music, cut with live video feeds off the dance floor to our projectors....Just traing right now staff for our launch of this service next season! I don't consider other photographers to be my competitors...I saw the videographer, and the dj as two guys toting around similar/compatible (digital multimedia) equipment, each getting a slice of my customers wedding budget....so I'm taking em' out with a single service that covers all three bases.