This behavior is designed to use as anti-spam solution e.g. for comments model. The basis of this solution is to use hidden fields in form and check if they are empty during validation. This is because most of spam-bots fill all fields in form. Real users doesn't
Second anti-spam solution is checking how long form is filled by submitter. Robots fills form really quick, while user need for that at least 1-2 seconds. Measuring time between creating model and saving it gives us answer if we are dealing with form filled by reals user of spam-bot.
Note, aim of this behavior is to avoid using captcha, as it isn't user friendly solution and it is not so good as it should be in spam filtering. Off course you can use this extension together with captcha to strengthen your anti-spam mechanism.
If you have any interesting solution I can add to this extension do not hesitate to write here.
I'm not complete idiot... some parts are missing!