Usually, if they give you a link to click for claiming your rewards, that's a link that allows them all your personal information - basically, a free pass to SEARCH your computer without you know. A free pass to hack your computer.

It's just like when you receive phone calls with people claiming they are the phone company and testing your line, asking you to press certain numbers - gives them free access to use your number as their own number and call anywhere in the world. Guess who has to pay the bill?

If it wasn't a scam, they wouldn't be emailing you about such a thing.