The appeal of a run/walk strategy at a marathon

So anybody that's run a marathon before will undoubtedly have seen pace bunnies that will have their designated pace time filtering throughout the start area and then if you run with them in the race you'll have noticed that they don't do a strict running at the pace that they'll need to hit the goal time.  Now there's been a lot some rumblings from both camps on either side putting forth some good evidence on why you should(n't) do it.  I tried it the other day on one of my longer runs and definitely I can see the appeal of doing it but I've come to some conclusions about this run walk strategy.

Doing a run walk is slow
Well straight forward logic would dictate to be likely true because if you're running at the same pace for 10 minutes and then suddenly plop in an extra 1 minute break of course you're going to be slower.  But the cool thing is you're actually probably going to be running a little bit quicker than your target pace and then when you take your one minute break and finish it you're not all that much slower.  You can also modify the amount of time spent running/walking to help change this a bit.  The other thing is that you will likely be a bit fresher in the end because you've give yourself 18 or more 1 minute breaks throughout your race which could be a huge deal.

You need to follow it if you're doing it
For example if you say I'm going to do 10 on 1 off, you need to follow it because it can be very easy to say hey I'll take another 30 seconds here, and then you're bit by bit not taking 1 minute but 1.5 or 2 so you need to follow it in order for it to work

Your body is not meant to run 3 hours plus straight
The reason for doing a run walk is to give your a rest in between because it's not built to do that, sure the winners will run the entire time, but the amount of time that they've dedicated in order to do that is absolutely unbelievable.

It requires some calculation
If you are going to succesfully pull this off (which you can, people have run sub 3:30's on a run walk strategy) you need to calculate roughtly if I go for 10 minutes, and walk for 1, how fast am I running, how fast am I walking, what kind of distance do you cover in that time so it is completely doable you just need to plan it out a wee bit.

~Cheers