What is the frequency of DDR4 RAM from 2133 to 3300 MHz for?

Question

Intel

Asked about updating the PC. The last socet from intel, as I understand it, is 1151. Naturally, motherboards for it come with DDR4. The top processors with socet 1151 that I found are Core i5-6600K and Core i7-6700. In the characteristics of these processors, the maximum frequency of supported RAM is declared - 2133 MHz. So why do we need bars with a frequency higher than 2133? If the processor paired with them still will not work faster than 2133 MHz. Well, if I understand correctly...

Answer 1

something like this
www.legitreviews.com/ddr4-memory-scaling-intel-z17...
and this, "top i7" like the whole i series supports a very high amount of memory, 64 (and sometimes even 32) - GB is not serious at all
compare with Xeon

Answer 2

The higher the frequency of the bus (conditionally RAM), the higher the frequency can be achieved when overclocking the processor.