The payout is simply TOO LOW to be useful.
If I would like to get 0.0001BTC, then I'd go to
http://bitcoincaptcha.org instead. The site is ugly, but it pays 0.0001btc per captcha solved, and you can solve as many as you like. It usually sends one payment per day, if you solved 100 captchas, you can one single payment of 0.01btc, instead of 100 0.0001btc.

I discovered your site yesterday. I did use it and then when I saw that he pay out was 0.0001 BTC, I realized that this was about 0.05 cents... If I set an alarm and used the site each hour all day then I'd make just over a penny!
I appreciate that this is free -- but boy... A penny for 24 log ons?