I know from experience, acrid electrical smoke and burnt electronics, that when you expect an outlet to be 120v because of the connector and you plug a 120v switched device into a 240v plug you're just kinda screwed. Best to have the 120v as C13 and 240v as C14. Makes life easier. The power distribution on my rack all runs C14 for this reason.
Their really isn't anything I can do about the fact that all the commonly available PSU's terminate in a C13 socket. All the better brands auto switch to 240v, and they all come with C13 sockets, not C14.
The male plug ends are NEMA 6-15 which is physically impossible to plug a stand NEMA 5-15 120V cord into, so it's not possible to accidentally plug something else into the 240v outlet. The only possibility for mistake is if you unplugged the C13 end of the cord from the mining rig and plugged it into another device which can't handle 240v. Which isn't going to happen.
Basicily if it's good end for Corsair, and it's good enough for the Underwriters Laboratory it's good enough for me.