If you have money to spend on an i7-5960X, you probably have enough to pay someone to tune it (overclock) for you.
where's the fun in that?
you need the power than 5ghs can enable but don't have the ability or knowledge to do it yourself, so instead of risking the processor not knowing what you are doing, pay someone who does to push it to its limits.
granted, single core performance will get the biggest benefit from this, all the heavy loads i would want to put on an 8 core cpu would be better served by a multi cpu motherboard and getting a few 6 core chips for less than 1 8 core cpu