You see, you program the keys. This is recommended for MMORPGs, like World of Warcraft, and MOBAs, like League of Legends, Dota 2, and other games of the category. This is not recommended for first-person shooters, though. Get a regular keyboard instead.

You can customize each and every button on the Razer Tartarus to your personal skillset.

Yes, as long as you have the proper software. But out of the box, yes again.

Why would you want to?

It depends on when you bought it and your Elite status.