Of course its up to you to use it, but I see many problems with this unlock method.

• Even here from a recording the password is guessed after about 10 attempts if users are not well educated about choosing a secure Password. Example here.
• Given time you can try reasonable combinations by hand
• Traces on screen give hints about the correct position.

It would be improved by a huge amount if you had to do 3 or 4 of such pictures.

Best would be if one could combine different unlock methods. E.g. do a picture-unlock and then (without feedback if you where correct) enter a Pin (number positions randomized).

This would combine the strengths of individual methods.