Because it will be much quieter and look better than the stock intel cooler
True but you can also get a Cryorig H7 for $10 more and it's much easier to install.
Benj__ :
no! because soon as posible i want to OC my i3 6100 with z170 mobo.
I don't think it's currently possible to overclock an i3 at the moment. Asrock has a work around with some of their new H170 series boards but right now all I'm seeing is that it's BCLK only (no change in voltage allowed, but multiplier and XMP is fine) and requires a dongle to work. Z170 won't overclock an i3 as far as I am aware.