What's the point of having a morgue? [duplicate]

I don't believe there's currently any effect on the mood or efficiency of your staff or prisoners.

However, there's still something to keep in mind: dead (and unconscious) characters can be looted. If a staff member dies, then prompt movement to a morgue can prevent prisoners from looting Staff Keys off the corpse. This is even more important when the corpse is a guard, since Jail Keys and weapons can be taken.

To a much less severe degree, storage of prisoner corpses in morgues will prevent access to any contraband they may have been carrying.

If you do build a morgue, you will have to ensure your morgue is properly protected to prevent prisoners from walking in and just taking the items from dead bodies.

There is no consequence for leaving corpses anywhere. All it does if leave a mark of failure in your path of making a fully functional prison.