I think it's just a matter of personal preference. I remember when everyone in Colorado still used rope to tie boats down. Everyone should know their knots from their SRT anyways. Straps are convenient and with just a little skill are not at all damaging to the car. I've never hit my car or window with the strap but unlike some of my buddies, I pay attention when I'm strapping boats down
. I have never lost a boat (had a few lucky ones, though). I use ropes occasionally but prefer strappage. Ropes are more versatile and cheaper but also tend to stretch more and take longer to tie down when taking out in the snow
For the record, I have trimmed straps down when they were too long (ones that I always use for the same purpose and knew I wouldn't miss the extra length).
I say, be good at doing both and choose what you want to do based on personal preference and what's available at the time.
"The owner of the car must always tie the boats on. He knows how he wants it done."-Corran Addison