People hold different values on different things. To some, this might be the only way they can get the device, or maybe the amount of money is trivial vs. getting something they want. About 5 minutes after the pre-order started, you couldn't get a jet black variant anymore until November. Some people don't want to wait that long, and if you have the means to make that happen, why not?
I know people personally who would rather spend more money on the device for convenience's sake than stay up all night trudging through a pre-order that has been historically pretty stressful for a lot of people (and proved, once again, to be the same way this year). Some people probably sat there and went "Why would someone stay up all night just to pre-order it when they could just wait and buy someone else's pre-order afterwards?" It's all about perspective.