Asset is good and efficient, however the demo implementation is exposing the captcha code and the verification can be easily bypassed, do not take the demo as an example of implementation.

Do NOT implement this captcha as is shown in the demo.  It exposes the 'secret' code to the client and can be easily 'hacked'. 
It is not a good implementation of a captcha.
The extension from the component can however be made part of a good captcha implementation, but needs more work so as to not expose the captcha code to the client. 

Very useful Captcha!
I needed to implement captcha quickly and it is very simple and easy to implement.