Absolutely asinine. I'm not compromising my account security for a chance to win a mount that I might use over the gorilla.

If you're using your real twitter account, you're potentially putting your real name, email, online handle and profile picture (if you have say, anime man X on Steam and Twitter), region and maybe even country (from the server and your name), character info, knowledge that you do in fact have an account worth trying to hack into with all the aforementioned, and who knows what else out there all in a neat package.