A simulated heart does not pump real blood. Also in the process, why should one start or stop at cell level, seems arbitrary, go further down to atoms and electrons etc. or go higher level to mental state or what not.
There are completed projects of smaller organism whose all neurons have been simulated, there hasn't been any revelations.
Our brain doesn't contain any 'data', so whoever decides to extract data from it will have to decide what the data will be or why it would be of any use. There has also been many objections made on why brain correlates are more or less useless on question of mind/intelligence.