Razer Tartarus - is it unnecessary or is it useful?

Hello everyone, I've been playing WoW for about a year now, and recently I've been considering getting some accessories to improve my gaming experience. Due to certain circumstances, my fingers often hurt, and my hands go numb, so I decided to look into the Razer Tartarus keypad.

Since this device isn’t cheap, I’d like to hear feedback from those who use it or similar accessories. How useful is it, and does it actually make gaming easier?

In case it matters, I mainly play as a Fury Warrior and Frost Mage.

Thanks in advance!