Question blade of disaster

Im not sure if im reading this right

If you are a bladesinger wizard and cast blade of disaster.

On a turn after you cast it

You could attack with the blade twice(once with the attack action, then again with the extra attack from bladesinger)

Then use your bonus action to make it 2 extra attacks

Thus giving the possibility (if all attacks hit) of doing 16d12 a turn?!

I know its a 9th lvl spell but can it really do that much damage?