I have some that are hard-wired, so I don't think it's a "reg'...?.
While those all sound like plausible answers, the correct answer is so you can strangle the drummer for hitting on your girlfriend for the last goddamned time without having to drag your entire amp over by the drums.
Damn rightIf you have loaded, humped, and installed a much electronic ***t as I have for as many years you would know how much I detest attached, grabby,dangly, flappy mains leads!
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FECK! Guitarists are a moaney bunch!
Dave.
Never would happen would it........ get to a gig and find that your detachable cable got left back home.
Maybe someone has one you could borrow, right?
That would be your own damn fault.
And you could always swipe one off a cash register or computer monitor or jukebox or video poker machine.