The "Account Giveaway" forms ask for your IP address, email, and Steam username. Combined, these allow hackers to attempt a password reset on your real account. You log in to play a free game, and a week later, your main account with 500 games is gone.
Steam allows "Family Library Sharing." However, if you share with a stolen or banned account, your primary account is flagged for association with fraudulent activity. Valve may revoke your ability to share games with your real family members. Free Steam Accounts With Games
Websites like SteamGifts allow users to give away unused Steam keys (from Humble Bundles or Fanatical). You enter raffles using points earned by giving away your own spare keys. It is a legitimate, community-driven economy. The "Account Giveaway" forms ask for your IP
Steam sales are legendary. A $70 game today is often $10 during the Winter/Summer sale. Instead of risking a virus for a stolen account, save $2 a week. Within two months, you can buy The Witcher 3 or Terraria legally. Steam allows "Family Library Sharing