The default Rails way of using Activerecord will automatically sainitize inputs for you. Not turning it into an associative array doesn't add anything to security.
User input need to be sanitized always. Rails make it easy and is the default way.
User input need to be sanitized always. Rails make it easy and is the default way.
Regardless, it's not a knock on rails. Just saying it's not necessarily a magic bullet to secure apps (and I don't believe rails nor PHP needs to be).