iMac 27” 5k late 2015 to wacom cintiq 27QHD

I need to purchase a longer display cable that runs from my iMac thunderbolt socket to my cintiq Display port.

the cable I have now is a 2m thunderbolt to thunderbolt cable, however a 3m thunderbolt cable costs £53.00.

It looks like mini display cables are much cheaper.

As the cintiq is labelled mini display would I be right in stating that I won’t gain anything from a thunderbolt cable anyway?

thanks