A http://en.wikipedia.org/wiki/http:/Father_of_All_Bombs is less dangerous than you might think. Lots of energy sure but it’s poorly directed and there is no poison afterward.

Cluster bombs’ are generally a bigger threat vs people. (ex: football stadium) Bunker busters are more useful vs. hardened structures. (Command center)

I have heard a suggestion that the world trade center would have likely survived a hit from a Father of all Bombs. Though the building would likely need to be condemned afterward.

PS: Aparently they are vary useful for cave systems though.