My guess is because they hear how good it is, and don't care that they won't use it. Given that most people that want it don't code yet?
What gets you to that point?
I didn't track, who of the people that are calling for Coda are actually coding but I'm sure many of them are.
I for my point would love to have, would certainly use it but I don't see a chance that it gets in any bundle. I will probably buy it anyway from the dev if I have money for software free at some point (which means there have to be a few months without a MacHeist bundle ;-) )