Why Jesus Christ said I saw Satan fall like lightning from heaven?

What a Joyful moment when the Children of God experienced the power of Lord's name very first time - Then the seventy returned with joy, saying, Lord, even the demons are subject to us in Your name - Luke 10:17

For heaven, Its like Mom watching her children taking the first step by his own and fighting against the power of darkness, that's when Christ said - I saw Satan fall like lightning from heaven - Luke 10:18b

And proclaiming Jesus Christ name is the secret of Christian life, and Father's name will be glorified only through by the name of Son Jesus Christ - Whatever you ask in my name, this I will do, that the Father may be glorified in the Son -  John 14:13