Are you suggesting the reef line goes from the end of the boom, through the clew and back to the end of the boom? If you are, that is definitely not ideal because that setup will not get the clew down to the boom (pulls only aft not down).Having your clews reefing line run from the outboard end of your boom up to a reefing point on the sail and back down to the boom does give you a bit of a purchase, it will also give you a more centred attachment point when reefed. As opposed to one side of the boom or the other it is pulling from both sides.
Running it to the mast is essential if you want to reef when off the wind, else how do you get to the end of (or even halfway down) the boom when it's out there over the water?Also we normally reef our sails way to late, so having it run forward toward the mast give you a safer and easier place to reef from.
Running a reefing line to the cockpit only helps if you have a single line reefing setup (many arguments for and against on this forum) because if you don't, you have to go to the mast anyway to get the luff down and secured.Running it to the cockpit is even better.