Even if a tiny figure could hold all the computer crap inside it and could actually know where bricks are and were they could be put, it would cost at least 2.000. Plus what if you lose the figure or break it? Do you honestly think your parents will be stupid enough to save up another 2,000 for you when you will probably break it or lose it again. Also how would it be able to walk and stuff? beside the reasons other people said it would still not now where to go unless it is a remote control robot. Even if it is a remote control robot how would you be able to see where it's going when you make it go inside a Lego building?
So the answer to your question is no.
In maybe 20 or 30 years when we have all the crap and it is actually possible ( which would take about 2 or 3 years just to make the first one) yes, I would buy it :).